Modern Heck Reactions - New Trends in Cross-Coupling: Theory and Applications - page 371

L

Ar OTf

O

Pd

L

base

R Ar

L Ar

Pd

TfO -

R

L

COAr

L

Pd

TfO -

L

CO

L Ar

TfO - TfO -

Pd

L COAr L CO

Pd

R

L

R

Scheme 9.25 The hypothetical catalytic cycle for carbonylative Heck reactions of
aryl triflates.

O

CO (2-5 bar)
[(c inna my l)PdC l] 2 (1 mol%)
d ppp, Et 3 N,PhMe,100°C,20h

OTf

+

N OMe

N MeO

86%

Scheme 9.26 Carbonylative Heck reaction of aryl triflates.

N

O

PAd 2

CO (5 bar)
[(cin namyl)P dCl] 2 (1 mol%),

N

I

(2)
Et 3 N, dioxane, 1 00°C, 20 h

OBu

+

OB u

77%

EtO

EtO

(2)

Scheme 9.27 Carbonylative Heck reaction of aryl halides using a bulky electron-rich
phosphine (2).

O

CO (5 atm), O 2 (5 atm)
Pd(OAc) 2, dppp
DMSO, 60°C

B(OH) 2

+

R R' R

55-97%

R'

Scheme 9.28 Oxidative deborylative carbonylative Heck reaction.

Beller and co-workers found a further extension of the carbonylative Heck
methodology and realized oxidative carbonylative Heck reactions using
arylboronic acids as nucleophilic coupling partners and oxygen as stoi-
chiometric oxidant (Scheme 9.28). 112
Intramolecular carbonylative cyclization involving an iodoalkane residue
is one of the rarest examples of the Heck reaction involving an sp 3 carbon, 113