Palladium-Catalyzed Carboformylation Enabled by a Molecular Shuffling Process
Hydroformylation, a reaction which installs both a C–H bond and an aldehyde group across an unsaturated substrate, is one of the most important catalytic reactions both in industry and academia. Given the synthetic importance of creating new C–C bonds, and the widespread academic and industrial impact of hydroformylation, the development of carboformylation reactions, wherein a new C–C bond is formed instead of a C–H bond, would bear enormous synthetic potential to rapidly increase molecular complexity in the synthesis of valuable aldehydes. However, the demanding complexity inherent in a four-component reaction, utilizing an exogenous CO source, has made the development of a direct carboformylation reaction a formidable challenge. Here, we describe a molecular shuffling strategy featuring the use of readily available aroyl chlorides as a carbon electrophile and CO source, in tandem with a sterically congested hydrosilane, to perform a stereoselective carboformylation of alkynes under palladium catalysis. An extension of this protocol to four chemodivergent carbonylations further highlights the creative opportunity offered by this molecular shuffling strategy in carbonylation chemistry.