Palladium-Catalyzed Markovnikov Hydroformylation of Olefins

Markovnikov hydroformylation of unactivated olefins represents a fundamental and highly valuable reaction for the formation of aliphatic branched aldehydes, but it remains challenging, because conventional hydroformylations typically exhibit anti-Markovnikov selectivity. Herein, we report a novel palladium-catalyzed Markovnikov hydroformylation of unactivated olefins to afford a series of branched aldehydes in high yields and with high regioselectivity. Crucial to the success of this reaction is the use of a unique neutral palladium catalyst coordinated with a novel (3',5'-bis(trifluoromethyl)-[1,1'-biphenyl]-2-yl)diphenylphosphane ligand, in conjunction with a silane-acetate acid system serving as the hydrogen surrogate. The mechanism of the reaction has been studied by several methods. The utility and versatility of this reaction are demonstrated by the efficient transformation of readily available olefins into high-value flavor and fragrance compounds.