Diastereoselective and Enantioselective Hydrophosphinylations of Conjugated Enynes, Allenes and Dienes via Synergistic Pd/Co Catalysis

Abstract

Different from the reported work focusing on the construction of single P‐ or C‐stereocenter via hydrophosphinylation of unsaturated carbon bonds, the highly diastereo‐ and enantioselective hydrophosphinylation reaction of allenes, conjugated enynes and 1,3‐dienes is achieved via a designed Pd/Co dual catalysis and newly modified masked phosphinylating reagent. A series of allyl motifs bearing both a tertiary C‐ and P‐stereocenter are prepared in generally good yields, >20 : 1 dr, >20 : 1 rr and 99 % ee. The unprecedented diastereo‐ and enantioselective hydrophosphinylation of 1,3‐enynes is established to generate skeletons containing both a P‐stereocenter and a nonadjacent chiral axis. The first stereodivergent hydrophosphinylation reaction is also developed to achieve all four P‐containing stereoisomers. The present protocol features the use of only 3‐minutes reaction time and 0.1 % catalyst, and with the observation of up to 730 TON. A set of mechanistic studies reveal the necessity and roles of two metal catalysts and corroborate the designed synergistic process.