Palladium-catalysed carboformylation of alkynes using acid chlorides as a dual carbon monoxide and carbon source

Hydroformylation, a reaction that installs both a C–H bond and an aldehyde group across an unsaturated substrate, is one of the most important catalytic reactions in both industry and academia. Given the synthetic importance of creating new C–C bonds, 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 palladium-catalysed strategy that uses 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. An extension of this protocol to four chemodivergent carbonylations further highlights the creative opportunity offered by this strategy in carbonylation chemistry. In an effort to extend the important hydroformylation reaction, a palladium-catalysed carboformylation reaction has now been developed in which two new carbon–carbon bonds are created across an alkyne. This modular reaction relies on a CO shuffling process and uses an acid chloride as a dual carbon and CO source.