Transition metal-catalyzed carbonylative coupling reaction for the
synthesis of polyfunctional biaryl ketones is attracted enormous
attention because their core structural scaffolds are commonly embedded
in various naturally occurring molecules,
Scheme 1. Pharmaceutical and biological significance of biaryl
ketones
pharmaceuticals, and agrochemical industries.[1]Some examples of naturally occurring biaryl ketones exhibit
extraordinary antitumor activity I ,[2]photosensitizers II ,[3] electric material
precursors III ,[4]
neoplastic agents IV ,[5] and anticancer
activity V (Scheme 1).[6] Given the
significance of biaryl ketones, considerable effort has gone into their
synthesis.
Conventionally, the biaryl ketone is synthesized using Friedel-Crafts
acylation of arene of acid anhydrides or aryl halides with Lewis’s acid.
However, this method’s use of the excess amount of Lewis acid causes
problems with various functional groups, resulting in a large amount of
waste and also suffering from regioselectivity.[7]In this regard, the transition metal-catalyzed carbonylative
cross-coupling reaction is a useful and simple technique for the
synthesis of polyfunctionalized biaryl ketones. Generally, transition
metal-catalyzed carbonylation reactions for the synthesis of biaryl
ketones can be broadly classified into three groups: a) Synthesis of
biaryl ketone via carbonylative cross-coupling reaction between organic
halides and nucleophilic organometallic
compounds.[8] This approach commonly allowed the
synthesis of both symmetric and unsymmetric biaryl ketones. b)
palladium-catalyzed homo-coupled reductive carbonylation of aryl halide
in the presence of reducing agents.[9] c)
carbonylative self-coupling reaction of nucleophilic organometallic
compounds under oxidizing agents.[10]
Over the past decades, various catalytic synthetic processes have been
established for the synthesis of symmetric biaryl ketones. The
transition metal-catalyzed aerobic oxidation of terminal olefins to form
symmetric and unsymmetric carbonyl compounds. The oxidative
self-coupling of aryl aldehydes via decarbonylation forms biaryl ketones
and biaryls (Scheme 1a, 1b).[11] Although these
transformations make an important contribution to biaryl ketones
synthesis, it suffers from the usage of moisture-sensitive ligands,
harsh reaction conditions, limited substrate scope, and longer reaction
time. Recently, several new synthetic approaches have been developed by
chemists to reduce these types of problems. The transition
metal-catalyzed carbonylative self-coupling reaction is the most
effective approach for transforming different functionalized ketones.
Recently, Wu and co-workers reported Bismuth-mediated synthesis of
symmetric biaryl ketone by oxidative carbonylation of triarylbismuthings
using m-CPBA (3-chloroperoxybenzoic acid) as an oxidant in chloroform
under high CO pressure (40 bar) (Scheme 1c).[12]