PAPER
Ca aly ic c oss-coupling o diazo compounds wi h
coinage me al-based ca alys s: an expe imen al and
heo e ical s udy†
I an Ri illa,
a
W. M. C. Samee a,
b
Eleu e io Al a ez,
c
M. Ma Díaz-Requejo,*
a
Feliu Mase as*
b,d
and Ped o J. Pé ez*
a
We examined he abili y o Tp
x
M (Tp
x
= hyd o is(py azolyl)bo a e ligand; M = Cu and Ag) and IP MCl
(IP = 1,3-bis(diisop opylphenyl)imidazol-2-ylidene; M = Cu, Ag, Au) complexes as ca alys p ecu so s o
he c oss-coupling o diazo compounds. Expe imen al da a showed ha he me al cen e can be uned
wi h he app op ia e selec ion o he ligand o yield ei he he homo- o he e o-coupling (c oss-coupling)
p oduc s. A compu a ional s udy o he eac ion mechanism allowed he a ionaliza ion o he expe i-
men al eac i i y pa e ns, and he iden ifica ion o he key eac ion s ep con olling he selec i i y: he
ini ial eac ion be ween he me alloca bene in e media e and one o he diazo compounds.
In oduc ion
The me al-ca alyzed ca bene ans e eac ion o diazo com-
pounds has cons i u ed a use ul me hodology in o ganic syn-
hesis, bo h in in e - and in amolecula ashions.
1
Du ing
his eac ion, unsa u a ed agmen s can be modi ied upon
addi ion o a CR
1
R
2
agmen o yield h ee membe ings
(Scheme 1). Also, sa u a ed X–Y bonds can be unc ionalized,
affo ding he co esponding inse ion p oduc s.
The main d awback o all hese eac ions consis s o he
non-desi ed side- eac ion ha o igina es om he coupling o
he me alloca bene in e media e wi h a second molecule o
he diazo eagen (Scheme 1). Fu he , his homocoupling
eac ion is a ou ed o e he addi ion/inse ion p ocesses,
al hough he use o a low diazo concen a ion usually p e-
cludes such coupling. Se e al g oups ha e explo ed his e-
ac ion as an al e na i e syn he ic ou e o ole in syn hesis, whe e he coupling o wo agmen s always de i es om
he same diazo eagen . The u henium-based sys ems we e
he commonly used ca alys s o his ans o ma ion,
2
and he
ansi ion me als om g oups 4–6
3
and 9–11 ha e also been
employed.
4
Hodgson and co-wo ke s desc ibed
5
he c oss-
coupling o wo diazoace a es o o mulae N
2
C(H)CO
2
R wi h
diffe en R g oups. Bu i was no un il e y ecen ly ha
Da ies and co-wo ke s ha e desc ibed a hodium-based ca a-
ly ic sys em o p omo e he efficien c oss-coupling o wo dis-
inc diazo compounds
6
wi h a e y high egioselec i i y
owa d he Eisome [eqn (1)].
ð1Þ
Scheme 1 Me al-ca alyzed ca bene ans e eac ions.
†Elec onic supplemen a y in o ma ion (ESI) a ailable: C ys allog aphic da a o
compound 4(CIF). Con o ma ional analysis o selec ed s uc u es. E alua ion o
s e ic/elec onic effec s h ough ONIOM calcula ions. To al ene gies and Ca e-
sian coo dina es o all epo ed s uc u es. CCDC 905569. Fo ESI and c ys allo-
g aphic da a in CIF o o he elec onic o ma see DOI: 10.1039/c2d 32439c
a
Labo a o io de Ca álisis Homogénea, Depa amen o de Química y Ciencias de los
Ma e iales, Unidad Asociada al CSIC, Cen o de In es igación en Química Sos enible
(CIQSO), Uni e sidad de Huel a, Campus de El Ca men s/n, 21007 Huel a, Spain.
E-mail: [email p o ec ed], [email p o ec ed]; Fax: +34-959219942
b
Ins i u e o Chemical Resea ch o Ca alonia (ICIQ), 43007 Ta agona, Ca alonia,
Spain. E-mail: [email p o ec ed]; Fax: (+34) 977 920 231
c
Ins i u o de In es igaciones Químicas, Cen o de In es igaciones Isla de La Ca uja,
A da Ame ico Vespucio 49, 41092 Se illa, Spain
d
Depa amen de Química, Uni e si a Au ònoma de Ba celona, 08193 Bella e a,
Ca alonia, Spain
:15.
View A icle Online
View Jou nal
| View Issue
We ha e desc ibed se e al ca aly ic sys ems based on he
g oup 11 me al complexes o he addi ion
7
o inse ion
8
o
CHCO
2
E (de i ed e hyl diazoace a e, EDA) o o ganic sub-
s a es. In iew o he in e es on he abo e c oss-coupling e-
ac ion, we ha e s udied he po en ial o ou ca alys s (Tp
x
Mand
IP MCl; Tp
x
= hyd o is(py azolyl)bo a e ligand; IP = N-he e o-
cyclic ca bene ligand) in his ans o ma ion, whe e we ha e
ound ha bo h he coppe and sil e can be uned wi h ligands
o affo d he o ma ion o desi ed ole ins. Theo e ical calcu-
la ions we e ca ied ou o a ionalize he mechanis ic de ails.
Resul s and discussion
Ca alys sc eening o he c oss-coupling eac ion o diazo
compounds
P e ious wo k ca ied ou in ou labo a o y has shown ha
wo amilies o g oup 11 me al-based ca alys s con aining
hyd o is(py azolyl)bo a e (Tp
x
)o N-he e ocyclic ca bene
(NHC) ligands (Scheme 2) eadily ans e ed ca bene uni s :
CHCO
2
E om e hyl diazoace a e (EDA, N
2
CHCO
2
E ) o se e al
sa u a ed o unsa u a ed subs a es.
7–9
The ca aly ic coupling
o wo ca bene g oups was obse ed as a side eac ion, and
his p ocess could be a oided by slow addi ion o EDA. The
a o emen ioned wo k by Da ies and co-wo ke s
6
guided us o
explo e he ca aly ic po en ial o hese compounds owa d he
coupling o wo diffe en diazo compounds wi h he aim o
inducing he syn hesis o he ole in de i ed om he c oss-
coupling o bo h ca benes.
In he i s se ies o expe imen s, we es ed he ca aly ic
ac i i y o se e al Tp
x
-con aining complexes in he c oss-
coupling eac ion o wo diffe en diazo compounds, EDA [A in
eqn (2)] and e hyl 2-phenyldiazoace a e [B in eqn (2)].
ð2Þ
We could expec he o ma ion o h ee ole ins: hose ha
a e coming om he homocoupling (1,2) and he a ge ed
he e ocoupling ole in (3) wi h bo h Zand Eisome s. As shown
in Table 1, he coppe -based ca alys s exclusi ely affo ded a
mix u e o die hyl uma a e and malea e (i.e., he homo-
coupling p oduc s om EDA). Nei he o he o he homo-
coupling ole in 2no he he e ocoupling 3we e de ec ed a he
end o he eac ion, and diazo compound Bwas eco e ed. In
con as , he analogous sil e -based complexes ga e 90% o
he a ge ed c oss-coupling p oduc 3, whe eas he homo-
coupling de i a i es 1and 2we e no o med. Diffe en E:Z
egioselec i i ies we e induced by bo h sil e ca alys s (Table 1,
en ies 4, 5). In e es ingly, a mino p oduc was also o med in
his case, and was iden i ied as an azine (4) ha o mally
de i ed om he coupling o wo molecules o diazo com-
pound Ba e he loss o a molecule o N
2
. Ye desc ibed,
10
we ha e unambiguously cha ac e ized compound 4by compa -
ing he li e a u e da a as well as by X- ay diff ac ion s udies
(see ESI†).
A e hese indings, we wonde i he complexes IP MCl
(IP = 1,3-bis(diisop opylphenyl)imidazol-2-ylidene; M = Cu, Ag
and Au) could be also ac i e o he eac ion shown in eqn (2),
gi en hei al eady commen ed capabili ies o ca bene ans-
e om EDA.
8a,b,11
Table 2 summa izes he esul s ha we
ha e ob ained. F om which, he ollowing in o ma ion can be
ex ac ed: (i) a halide sca enge (NaBA
′
4
(A ′= 3,5-bis( i luo o-
me hyl) phenyl)) is equi ed o he eac ion o occu wi h he
Cu- and Ag-based ca alys s; (ii) he gold complex emained
ca aly ically inac i e wi h and wi hou such a sca enge . Wi h
coppe (Table 2, en y 2), homocoupling o EDA was obse ed
as he mino p oduc , while he c oss-coupling p oduc , 3,was
ob ained as he main p oduc (89%). A simila esul was
obse ed wi h he sil e analogue, bu wi h he lack o 1.
Scheme 2 Ligands employed in his wo k.
Table 1 C oss-coupling o diazo compounds Aand Bca alysed by Tp
x
M(M=
Cu, Ag)
a
En y Ca alys 1:2:3:4(%) E:Z(3)
1
b
Tp
B 3
Cu 100:0:0:0 —
2
b
Tp
Ph
Cu 100:0:0:0 —
3
b
CuI 100 : 0 : 0 : 0 —
4Tp
*,B
Ag 0 : 0 : 90 : 10 78 : 22
5Tp
B 3
Ag 0 : 0 : 90 : 10 58 : 42
a
Reac ion condi ions: 0.0125 mmol ca alys ; 5 mL CH
2
Cl
2
; 0.25 mmol
o each diazo compound a 5 °C.
b
The diazo compound B emained
un eac ed in he eac ion mix u e.
Table 2 C oss-coupling o diazo compounds Aand Busing IP MCl (M = Cu, Ag
and Au) as a p eca alys
a
En y Ca alys 1:2:3:4(%) E:Z(3)
1 IP CuCl ——
2 IP CuCl + NaBA
′
4
5 : 0 : 89 : 6 76 : 24
3 IP AgCl ——
4 IP AgCl + NaBA
′
4
0 : 0 : 91 : 9 80 : 20
5
b
IP AuCl + NaBA
′
4
——
a
Reac ion condi ions: 0.0125 mmol ca alys ; 5 mL CH
2
Cl
2
; NaBA
′
4
(1 equi .); 0.25 mmol diazo compounds a 5 °C.
b
Bo h diazo
compounds emain un eac ed in he eac ion mix u e.
Again, homocoupling o he diazo compound B(i.e., ole in 2)
was no de ec ed. The E:Z a io o 3was simila wi h bo h
me als (en ies 2 and 4), indica ing a simila ca aly ic pocke .
The azine, 4, was also o med o a simila ex en o ha in he
Tp
x
M sys em. I is wo h men ioning ha he expe imen s
we e ca ied ou upon addi ion o he diazo compounds in one
po ion a he beginning o he eac ion.
The op imized esul s shown in Tables 1 and 2 we e
ob ained a 5 °C, and no signi ican eac ion ou come was
obse ed below his empe a u e. When he eac ions we e
ca ied ou a oom empe a u e (23 °C) wi h Tp
*,B
Ag and
IP AgCl as ca alys p ecu so s, he 1:2:3:4 a io o p oduc s
ound a he end o he eac ion was 0 : 0 : 57 : 43 and
0 : 0 : 47 : 53, espec i ely. Fu he , bo h ca alys s p o ide a sig-
ni ican inc ease o he azine, 4. The E/Zselec i i y did no
change wi h he empe a u e.
The abo e expe imen al da a ha e shown ha Tp
x
Ag and
IP MCl (M = Cu and Ag) complexes a e ac i e ca alys s o he
c oss-coupling eac ion o N
2
C(H)CO
2
E and N
2
C(Ph)CO
2
E o
affo d he desi ed he e ocoupling-de i ed ole ins 3. Fu he ,
his is he i s example o g oup 11 me al-based ca alys s o
his eac ion a hose le els o efficiency. A mino p oduc was
iden i ied as he azine (4). On he o he hand, he Tp
x
Cu
sys em exclusi ely led o he homocoupling p oduc s, 1. The e-
o e, he e is a clea effec o he ligand (Tp
x
s. IP ) in he
coppe case as well as an effec o he me al, Cu s. Ag, in he
Tp
x
case. In o de o asce ain he na u e o he mechanism
ha go e ns his ans o ma ion, a comple e heo e ical s udy
has been ca ied ou wi h bo h he Tp
B 3
M (M = Cu, Ag) and
IP MCl sys ems (M = Cu, Ag, Au), which is he subjec o he
nex sec ion.
Compu a ional s udies
The p oposed mechanism o he eac ion o N
2
C(Ph)CO
2
E
(6a) and N
2
C(H)CO
2
E (6b) ca alyzed by Tp
x
M(5) is shown
in Scheme 3. The i s s ep o his mechanism is he coo di-
na ion o 6a and 6b o he ca alys (5). S a ing om he esul -
ing complexes (7a and 7b), N
2
dissocia ion leads o he ac i e
me alloca bene in e media es 8a and 8b ia TS1a and TS1b,
espec i ely. These me alloca benes can eac wi h N
2
C(Ph)-
CO
2
E (6a)o N
2
C(H)CO
2
E (6b) o o m he c oss-coupling
(CC) p oduc (3), homocoupling (HC) p oduc s (1and 2), and
azine (AZ, 4) (see Fig. S1a, ESI†). The c oss-coupling and
homocoupling p ocesses unde go h ough TS2. I is well-
known om he li e a u e
12
ha TS2 should ha e an an ipe i-
plana a angemen o he M–C and C–N bonds, bu his
lea es s ill some con o ma ional lexibili y associa ed wi h he
app oach o he wo agmen s. We epo he e only he mos
s able con o ma ion o TS2, in o ma ion on he con o ma ion-
al sea ch can be ound in he ESI†sec ion.
Tp
B 3
M sys ems
Fi s , we compu ed he ee ene gy p o iles o he eac ion
o N
2
C(Ph)CO
2
E (6a) and N
2
C(H)CO
2
E (6b) ca alyzed by
Tp
B 3
Ag. Resul s a e summa ized in Scheme 4A. Coo dina ion
o 6a and 6b on Tp
B 3
Ag is ende gonic by +9.5 (7a) and +5.0
(7b) kcal mol
−1
, espec i ely. The key s ep happens o be he
subsequen N
2
elimina ion om 7a, leading o he me allo-
ca bene 8a h ough ansi ion s a e TS1a wi h a ela i e ene gy
o 19.8 kcal mol
−1
. In a simila ein, he second me allo-
ca bene, 8b, can be o med h ough TS1b wi h a ela i e ene gy
o 22.0 kcal mol
−1
. This s ep is c i ical because i cons i u es he
highes ene gy poin in pa hways leading o he p oduc s. The
ela i e ene gies o TS1a and TS1b indica e ha in he case o
Tp
B 3
Ag, N
2
C(Ph)CO
2
E will eac be o e ha N
2
C(H)CO
2
E . We
analyze he o igin o he disc imina ion on he eac ion o he
i s diazo molecule wi h he me al complex h ough ONIOM-
(B3LYP : MM3) calcula ions wi h a mechanical embedding
scheme (see Fig. S2, ESI†). This p o ed ha he eason is pu ely
elec onic, when using an MM desc ip ion o phenyl he dis-
c imina ion disappea ed.
S a ing om he a ou ed me alloca bene (8a), wo close
ene gy compe ing pa hways lead o c oss-coupling p oduc (3)
and azine (4), h ough ansi ion s a es wi h ela i e ee ene -
gies o 11.8 kcal mol
−1
(TS2
CC
) and 12.3 kcal mol
−1
(TS
AZ
),
espec i ely. Fu he , hese wo ansi ion s a es yield he 3:4
a io o 70 : 30, which is in easonable ag eemen wi h he
expe imen al alue (90 : 10). The mos s able ansi ion s a es
leading o he Eand Z o ms o he c oss-coupling p oduc s
hold he ba ie heigh s o 11.8 and 11.9 kcal mol
−1
, gi ing
ise o he compu ed E:Z a io o 54 : 46, which is in ag ee-
men wi h he expe imen ally obse ed alue (58 : 42). In bo h
ansi ion s a es, Ag–C and C–N bonds a e in he an ipe i-
plana con o ma ion (Scheme 3). The a ou able c oss-coupling
p oduc , 3(E), is −81.1 kcal mol
−1
below he en y channel
Scheme 3 P oposed ca aly ic cycle o he eac ion o N
2
C(Ph)CO
2
E (6a) and
N
2
C(H)CO
2
E (6b) ca alyzed by Tp
x
M (M = Ag, Cu).
(no shown in he ee ene gy p o ile). The al e na i e pa hway
leading o he homocoupling p oduc (2) om8a mus be dis-
ca ded because o he high ba ie o he ansi ion s a e
(22.9 kcal mol
−1
o TS2
HC
, mo e han 10 kcal mol
−1
han he
compe ing pa hways). The e o e, he e is a s ong p e e ence
o N
2
C(H)CO
2
E o be he second subs a e o eac wi h he
sys em. We a ibu e his p e e ence o s e ic effec s, as he
sys em becomes oo c owded o accep a second subs a e con-
aining a phenyl g oup.
Fo he sake o comple ion, we also checked he ba ie s o
he homocoupling and c oss-coupling s a ing om he less
a ou able me alloca bene, 8b, ed lines in Scheme 4A. The
ee ene gies o he co esponding ansi ion s a es a e p ohi-
bi i ely high 21.5 kcal mol
−1
(TS
HC′
) and 23.2 kcal mol
−1
(TS
CC′
) o compe e wi h he pa hways h ough 8a.I ishowe e
wo h ema king ha he en y o 6a as a second subs a e
molecule, leading in his case o homocoupling, is also
a ou ed.
Calcula ed ee ene gy p o iles o he analogous Tp
B 3
Cu
sys em a e shown in Scheme 4B. The mos s iking diffe ence
is ha now he o ma ion o 8b has a lowe ee ene gy ba ie
(19.5 kcal mol
−1
) han ha o 8a (22.6 kcal mol
−1
). This is due
o he ac ha he coo dina ion o N
2
C(Ph)CO
2
E o he
Tp
B 3
Cu is difficul , as he Cu-coo dina ion sphe e (i.e.,Cu–
ligand bond dis ances) is ela i ely smalle han he Ag-based
sys em (Fig. 1). As a esul , compu ed ee ene gies o 7a and
he subsequen ansi ion s a e o he N
2
dissocia ion a e ela-
i ely highe in ene gy. The e o e, 8b is he ac i e me allo-
ca bene in e media e in solu ion. S a ing om 8b, binding o
N
2
C(H)CO
2
E as he second diazo molecule is a o ed due o
s e ic easons, analogously o he sil e sys em. Howe e , in
his case binding o a second uni o 6b leads o he homo-
coupling p oduc .
IP MCl sys ems
Acco ding o he expe imen al obse a ions, IP CuCl and
IP AgCl sys ems canno pe o m c oss-coupling o N
2
C(Ph)-
CO
2
E and N
2
C(H)CO
2
E , and hey only become ac i e in he
p esence o a base, NaBA
′
4.
This obse a ion and p e ious
epo s in he li e a u e
11
sugges ed ha NaBA
′
4
could abs ac
Cl
−
om IP MCl, leading he ac i e p ecu so s, IP M
+
ha may
ini ia e he ca aly ic cycle. Howe e , he Au-based sys em is no
ac i e o c oss-coupling o homocoupling. We ca ied ou DFT
calcula ions o unde s and hese puzzling obse a ions.
Ou calcula ions (summa ized in Scheme 5) indica ed ha
i is mo e difficul o o m he IP M
+
ac i e species om he
s a ing IP MCl + NaBPh
4
in he case o gold. The ela i e ene -
gies a e 19.5 kcal mol
−l
o he coppe sys em, 21.9 kcal mol
−l
o he sil e sys em, and 28.0 kcal mol
−l
o he gold sys em.
As a esul , he a ailabili y o IP Au
+
will be lowe han ha o
IP Cu
+
and IP Ag
+
, which explains he in e io eac i i y o he
gold sys em. This is no in con adic ion wi h he efficiency o
he IP AuCl + EDA sys em o o he p ocesses such as C–H
Scheme 4 F ee ene gy p ofiles (kcal mol
−1
) o he eac ion o N
2
C(Ph)CO
2
E (6a) and N
2
C(H)CO
2
E (6b) ca alyzed by (A) Tp
B 3
Ag and (B) Tp
B 3
Cu.
Fig. 1 Op imised s uc u es o 7a: (A) Ag-based sys em and (B) Cu-based
sys em.
ac i a ion,
11
because he eac i i y depends bo h on concen-
a ion and ene gy ba ie .
13
Ou expe imen al esul s showed ha bo h he IP Cu
+
and
IP Ag
+
sys ems p e e c oss-coupling a he han homo-
coupling. Acco ding o he ee ene gy p o iles (Scheme 6), N
2
dissocia ion om N
2
C(Ph)CO
2
E bound complex (7a) is easie
han he N
2
C(H)CO
2
E bound species (7b) in bo h sys ems.
The e o e, he eac ion passes h ough he me alloca bene 8a,
leading o he desi ed c oss-coupling p oduc , 3. In he case o
IP Ag
+
,Eand Z o ms o 3a e o med wi h ba ie s o 15.5 and
18.2 kcal mol
−1
, espec i ely. Fu he , he calcula ed E:Z a io o
99 : 1 ep oduced he expe imen al end (E:Z= 80 : 20).
Simila ea u es can be seen o he analogous Cu-based
sys em, whe e he calcula ed ba ie s o he E(17.8 kcal mol
−1
)
and Z(20.4 kcal mol
−1
) p oduc s yield he E:Z a io o 99 : 1,
which also suppo s he expe imen al obse a ions (76 : 24).
We obse ed azine as a side p oduc wi h bo h he
ca alys s, and ou calcula ed 3:4 a io o 99 : 1 o he Ag-
based sys em and 100 : 0 o he Cu-based sys em suppo
he expe imen al ends. I is impo an o no e ha he
IP Cu
+
sys em p o ides homocoupling p oduc (2)asa
mino p oduc due o he ac ha he ene gy sepa a ion
be ween TS1a and TS1b is only 2.6 kcal mol
−1
, and he e o e
he me alloca bene 8b can be o med. Howe e , we did
no obse e homocoupling p oduc (1) in he case o
IP Ag
+
, because he ene gy gap be ween TS1a and TS1b is
5.5 kcal mol
−1
.
Ou calcula ions ep oduce all expe imen al obse a ions,
and p o ides a simple a ionaliza ion o hem. Compu a ional
chemis y is hus a p omising ool o he e alua ion o he
po en ial efficiency o new ligands o his chemical p ocess
p io o hei expe imen al es ing.
Conclusions
We ha e shown ha Tp
x
Ag and IP MCl + NaBA ′
4
(M = Cu and
Ag) complexes a e ac i e ca alys s o he c oss-coupling eac-
ion o N
2
CHCO
2
E and N
2
C(Ph)CO
2
E o affo d he e ocoupled
ole ins E O
2
C(H)C C(Ph)CO
2
E , which cons i u e he i s
example o g oup 11 me al-based ca alys s a his le el o
efficiency. The ela ed Tp
x
Cu complexes exclusi ely lead o he
Scheme 5 F ee ene gy p ofiles (kcal mol
−1
) o he o ma ion o IP M
+
om
IP MCl.
Scheme 6 F ee ene gy p ofiles (kcal mol
−1
) o he eac ion o N
2
C(Ph)CO
2
E and N
2
C(H)CO
2
E ca alyzed by (A) IP Ag
+
and (B) IP Cu
+
.

homocoupling p oduc s, E O
2
C(H)C C(H)CO
2
E . IP AuCl
does no eac unde simila condi ions.
This di e se eac i i y could be explained by a compu-
a ional s udy on he eac ion mechanism. The eac ion akes
place in a mononuclea complex, wi h one diazo compound
eac ing sequen ially a e he o he . In all eac ing sys ems
excep Tp
x
Cu, he ini ial eac ion wi h N
2
C(Ph)CO
2
E is a o ed
because o elec onic easons.
The second diazo compound o eac is always N
2
C(H)-
CO
2
E due o s e ic easons. As a esul , he he e o-
coupling p oduc is ob ained om Tp
x
Ag and IP MCl (M = Cu
and Ag), and he homocoupling p oduc om Tp
x
Cu. The lack
o eac i i y o IP AuCl is sa is ac o ily explained by he highe
ene gy cos o displacemen o he Cl
−
g oup o p oduce he
ac i e ca alys .
Expe imen al sec ion
Gene al manipula ions
All expe imen s we e pe o med using con en ional acuum
line and Schlenk echniques o in a d ybox. The complexes
Tp
x
M
14
and IP MCl
15
we e p epa ed acco ding o li e a u e
p ocedu es as well as he diazo compounds e hyl-2-diazo-
ace a e-2-phenylace a e
16
and NaBA ′
4
(A ′= e akis(3,5-bis-
( i luo ome hyl)phenyl)bo a e).
17
E hyl diazoace a e was pu -
chased om Sigma Ald ich. NMR spec a we e eco ded a
298 K using a Va ian Me cu y 400 ins umen . GC we e un in
a Va ian 3900 model.
Gene al ca aly ic eac ion
In a ypical expe imen , he ca alys (0.0125 mmol) was dis-
sol ed in 5 mL o he CH
2
Cl
2
. In he case o IP MCl complexes,
1 equi . o NaBA
4
′was added o he abo e solu ion. Then,
e hyl-2-diazoace a e (0.25 mmol) and e hyl-2-diazoace a e-
2-phenylace a e (0.25 mmol) we e added in one po ion. The
eac ion mix u e was s i ed a 5 °C un il no diazo eagen s
we e de ec ed by GC. The ola iles we e emo ed unde
acuum, and he esidue was pu i ied by SiO
2
-column
ch oma og aphy wi h AcOE –pe oleum e he (10 : 1). NMR
s udies e ealed he o ma ion o h ee p oduc s (see eqn (2)).
The compounds we e iden i ied by compa ing wi h he li e a-
u e da a.
10,18
Compu a ional de ails
All calcula ions we e pe o med using DFT wi h he B3LYP
unc ional as implemen ed in he Gaussian09 p og am.
19
The
LanL2DZ
20
basis se and associa ed effec i e co e po en ials
wi h a single pola iza ion unc ion we e used o Ag (1.611),
Cu (3.525), and a d pola iza ion was added o B (0.4280).
21
The 6-31G(d) basis se was used o he C, H, N, O, and B
a oms.
22
The SMD app oach o T uhla and co-wo ke s was
applied o sol a ion ea men s,
23
whe e dichlo ome hane (ε=
8.93) was used as he sol en . All s uc u e op imiza ions we e
ull in he sol en phase wi h no es ic ions, and ib a ional
equency calcula ions we e pe o med in o de o con i m
ha he s a iona y poin s we e minima o ansi ion s a es. All
ansi ion s a es had a single imagina y equency in he
op imiza ion in sol en phase. F ee ene gy co ec ions a
298.15 K and 10
5
Pa p essu e we e used, including ze o poin
ene gy co ec ions. Connec i i y o he ansi ion s a e s uc-
u es was con i med by elaxing he ansi ion s a e geome y
owa ds bo h he eac an and he p oduc . Single-poin es
calcula ions wi h M06 and B97D p oduced sligh ly wo se
ag eemen wi h expe imen han he B3LYP calcula ions, he e
seems o be some p oblem wi h he in oduc ion o dispe sion
co ec ions in hese sys ems.
Hyb id quan um mechanics/molecula mechanics
(QM : MM)
24
calcula ions we e pe o med wi h a new ONIOM-
(DFT : MM3) implemen a ion de eloped by ou g oup, whe e
we used he Gaussian09 s anda dized in e ace o un
Tinke 6.0.
25
Acknowledgemen s
We hank MINECO (CTQ2011-28942-CO2-01, CTQ2011-27033
and Consolide Ingenio 2010 CSD2006-0003), Jun a de
Andalucía (P oyec o P10-FQM-06292), Gene ali a de Ca alunya
(2009SGR-2059 and Xa xa de Re e ència en Química Teò ica i
Compu acional) and he ICIQ Founda ion o inancial
suppo .
No es and e e ences
1(a) M. P. Doyle, R. Duffy, M. Ra niko and L. Zhou, Chem.
Re ., 2010, 110, 704–724; (b) M. P. Doyle, M. A. McKe ey
and T. Ye, Mode n Ca aly ic Me hods o O ganic Syn hesis
wi h Diazo Compounds, John Wiley & Sons, New Yo k, 1998;
(c) G. Maas, Top. Cu . Chem., 1987, 137,75–253.
2 Ru henium-based ca alys s: (a) L. K. Woo and D. A. Smi h,
O ganome allics, 1992, 11, 2344–2346; (b) J. P. Collman,
E. Rose and G. D. Venbu g, J. Chem. Soc., Chem. Commun.,
1993, 934–935; (c) W. Ba a a, A. D. Zo o and P. Rigo,
Chem. Commun., 1997, 2163–2164; (d) W. Ba a a,
A. D. Zo o and P. Rigo, O ganome allics, 1999, 18, 5091–
5096; (e) E. G aban and F. R. Lemke, O ganome allics, 2002,
21, 3823–3826; ( ) G.-Y. Li and C.-M. Che, O g. Le ., 2004,
6, 1621–1623.
3 G oups 4–6 me al-based ca alys s: (a) J. Goux, P. L. Gend e,
P. Richa d and C. Moïse, J. O ganome . Chem., 2006, 691,
3239–3244; (b) J. P eiffe and K. H. Dö z, Angew. Chem., In .
Ed. Engl., 1997, 36, 2828–2830; (c) D. Jan, F. Simal,
A. Demonceau, A. F. Noels, K. A. Ru ano , N. A. Us ynyuk
and D. N. Gou e i ch, Te ahed on Le ., 1999, 40, 5695–
5699; (d) Z. Zhu and J. H. Espenson, J. Am. Chem. Soc.,
1996, 118, 9901–9907.
4 G oups 9–11 me al-based ca alys s: (a) T. Kubo,
S. Sakaguchi and Y. Ishii, Chem. Commun., 2000, 625–626;
(b) H. Bock and H. P. Wol , J. Chem. Soc., Chem. Commun.,
1990, 690–692; (c) T. Oshima and T. Nagai, Te ahed on
Le ., 1980, 21, 1251–1254.
5 D. M. Hodgson and D. Ang ish, Chem.–Eu . J., 2007, 13,
3470–3479.
6 J. H. Hansen, B. T. Pa , P. Pelph ey, Q. Jin, J. Au schbach
and H. M. L. Da ies, Angew. Chem., In . Ed., 2011, 50,1–6.
7 Addi ion eac ions. Cyclop opana ion: (a) M. M. Díaz-
Requejo, A. Caballe o, T. R. Belde aín, M. C. Nicasio,
S. T o imenko and P. J. Pé ez, J. Am. Chem. Soc., 2002, 124,
978–983; Cyclop opena ion: (b) M. M. Díaz-Requejo,
M. A. Mai ena, T. R. Belde aín, M. C. Nicasio, S. T o imenko
andP.J.Pé ez,Chem. Commun., 2001, 1804–1805.
8 Inse ion eac ions. C–H bonds: (a) M. M. Díaz-Requejo
and P. J. Pé ez, Chem. Re ., 2008, 108, 3379–3394;
(b) M. M. Díaz-Requejo, T. R. Belde ain, M. C. Nicasio and
P. J. Pé ez, Dal on T ans., 2006, 5559–5566. N–H bonds:
(c) M. E. Mo illa, M. M. Díaz-Requejo, T. R. Belde aín,
M. C. Nicasio, S. T o imenko and P. J. Pé ez, Chem.
Commun., 2002, 2998–2999; O–H bonds: (d) M. E. Mo illa,
M. M. Díaz-Requejo, T. R. Belde aín, M. C. Nicasio,
S. T o imenko and P. J. Pé ez, O ganome allics, 2003, 22,
2914–2918.
9 Fo e iews see: (a) M. M. Díaz-Requejo and P. J. Pé ez,
J. O ganome . Chem., 2005, 690, 5441–5450; (b) M. M. Díaz-
Requejo and P. J. Pé ez, J. O ganome . Chem., 2001, 617,
110–118.
10 R. Glase , G. S. Chen and C. L. Ba nes, J. O g. Chem., 1993,
58, 7446–7455.
11 (a) M. R. F uc os, T. R. Belde ain, P. de F émon ,
N. M. Sco , S. P. Nolan, M. M. Díaz-Requejo and
P. J. Pé ez, Angew. Chem., In . Ed., 2005, 44, 5284–5288;
(b) M. R. F uc os, P. de F émon , S. P. Nolan, M. M. Díaz-
Requejo and P. J. Pé ez, O ganome allics, 2006, 25, 2237–
2241.
12 (a) D. S. Wul man, B. W. Peace and R. S. McDaniel J .,
Te ahed on, 1976, 32, 1251–2155; (b) T. Oshima and
T. Nagai, Te ahed on Le ., 1980, 21, 1251–2154;
(c) B. K. R. Shanka and H. Shech e , Te ahed on Le .,
1982, 23, 2277–2280; (d) J. Hansen, J. Au schbach and
H. M. L. Da ies, J. O g. Chem., 2009, 74, 6555–6563;
(e) J. H. Hansen, B. T. Pa , P. Pelph ey, Q. Jin,
J. Au schbach and H. M. L. Da ies, Angew. Chem., In . Ed.,
2011, 50, 2544–2548.
13 A. A. C. B aga, E. Ál a ez, A. Caballe o, J. U bano,
M. M. Díaz-Requejo, P. J. Pé ez and F. Mase as, Chem-
Ca Chem, 2011, 3, 1646–1652.
14 (a) C. Mealli, C. S. A cus, J. L. Wilkinson, T. J. Ma ks and
J. Ibe s, J. Am. Chem. Soc., 1976, 98, 711–718;
(b) J. L. Schneide , S. M. Ca ie , C. E. Ruggie o,
V. G. Young J . and W. B. Tolman, J. Am. Chem. Soc., 1998,
120, 11408–11418; (c) M. A. Mai ena, J. U bano, J. Ca bajo,
J. J. Ma a e , E. Al a ez, M. M. Díaz-Requejo and P. J. Pé ez,
Ino g. Chem., 2007, 46, 7428–7435.
15 (a) V. Ju kauskas, J. P. Sadighi and S. L. Buchwald, O g.
Le ., 2003, 5, 2417–2420; (b) H. Kau , F. K. Zinn,
E. D. S e ens and S. P. Nolan, O ganome allics, 2004, 23,
1157–1160; (c) L. Dang, Z. Lin and T. B. Ma de , O gano-
me allics, 2010, 29, 917–927; (d) M. Delgado-Rebollo,
Á. Bel án, A. P ie o, M. M. Díaz-Requejo, A. M. Echa a en
and P. J. Pé ez, Eu . J. Ino g. Chem., 2012, 9, 1380–1386.
16 S. Bachmann, D. Fielenbach and K. A. Jø gensen, O g.
Biomol. Chem., 2004, 2, 3044–3049.
17 (a) M. B ookha , B. G an and A. F. Volpe, O ganome allics,
1992, 11, 3920–3922; (b) H. Iwamo o, T. Sonoda and
H. Kobayashi, Te ahed on Le ., 1983, 24, 4703–4706.
18 (a) D. A oiac, L. Rombinaic, H. Mani-Ronchin and
G. Ve a do, J. Chem. Soc., Chem. Commun., 1981, 541–542;
(b) L. Zhou, W. Zhang and H. F. Jiang, Sci. China, Se B:
Chem., 2008, 51, 241–247.
19 M. J. F isch, G. W. T ucks, H. B. Schlegel, G. E. Scuse ia,
M. A. Robb, J. R. Cheeseman, G. Scalmani, V. Ba one,
B. Mennucci, G. A. Pe e sson, H. Naka suji, M. Ca ica o,
X. Li, H. P. H a chian, A. F. Izmaylo , J. Bloino, G. Zheng,
J. L. Sonnenbe g, M. Hada, M. Eha a, K. Toyo a, R. Fukuda,
J. Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O. Ki ao,
H. Nakai, T. V e en, J. A. Mon gome y J ., J. E. Pe al a,
F. Oglia o, M. Bea pa k, J. J. Heyd, E. B o he s,
K. N. Kudin, V. N. S a o e o , R. Kobayashi, J. No mand,
K. Ragha acha i, A. Rendell, J. C. Bu an , S. S. Iyenga ,
J. Tomasi, M. Cossi, N. Rega, J. M. Millam, M. Klene,
J. E. Knox, J. B. C oss, V. Bakken, C. Adamo, J. Ja amillo,
R. Gompe s, R. E. S a mann, O. Yazye , A. J. Aus in,
R. Cammi, C. Pomelli, J. W. Och e ski, R. L. Ma in,
K. Mo okuma, V. G. Zak zewski, G. A. Vo h, P. Sal ado ,
J. J. Dannenbe g, S. Dapp ich, A. D. Daniels, Ö. Fa kas,
J. B. Fo esman, J. V. O iz, J. Cioslowski and D. J. Fox,
GAUSSIAN 09 (Re ision A.1), Gaussian, Inc., Walling o d CT,
2009.
20 (a) P. J. Hay and W. R. Wad , J. Chem. Phys., 1985, 82, 270–
283; (b) W. R. Wad and P. J. Hay, J. Chem. Phys., 1985, 82,
284–298; (c) P. J. Hay and W. R. Wad , J. Chem. Phys., 1985,
82, 299–310.
21 (a) A. Höllwa h, M. Böhme, S. Dapp ich, A. W. Ehle s,
A. Gobbi, V. Jonas, K. F. Köhle , R. S egmann, A. Veldkamp
and G. F enking, Chem. Phys. Le ., 1993, 208, 237–240.
22 (a) W. J. Heh e, R. Di ch ield and J. A. Pople, J. Chem. Phys.,
1972, 56, 2257–2261; (b) P. C. Ha iha an and J. A. Pople,
Theo . Chim. Ac a, 1973, 28, 213–222; (c) M. S. Go don,
Chem. Phys., 1980, 76, 163–168.
23 A. V. Ma enich, C. J. C ame and D. G. T uhla , J. Phys.
Chem. B, 2009, 113, 6378–6396.
24 (a) G. Ujaque and F. Mase as, S uc . Bonding, 2004, 112,
117–149; (b) T. V e en, K. S. Byun, I. Koma omi,
S. Dapp ich, J. A. Mon gome y, K. Mo okuma and
M. J. F isch, J. Chem. Theo y Compu ., 2006, 2, 815–826;
(c) C. Bo and F. Mase as, Dal on T ans., 2008, 2911–2919;
(d) W. M. C. Samee a and F. Mase as, WIREs Compu . Mol.
Sci., 2012, 2, 375–385.
25 (a) P. Ren and J. W. Ponde , J. Phys. Chem. B, 2003, 107,
5933–5947; (b) M. J. Schniede s and J. W. Ponde , J. Chem.
Theo y Compu ., 2007, 3, 2083–2097; (c) P. Ren, C. Wu and
J. W. Ponde , J. Chem. Theo y Compu ., 2011, 7, 3143–3161.