Palladium-catalyzed reactions of hypophosphorous compounds with allenes, dienes, and allylic electrophiles: methodology for the synthesis of allylic h-phosphinates.

摘要: Hypophosphorous compounds (MOP(O)H2, M = H, R3NH) effectively participate in metal-catalyzed C−P bond-forming reactions with allenes, dienes, and activated allylic electrophiles under mild conditions. The catalytic system Pd2dba3/xantphos is crucial to avoid or minimize the competitive reductive transfer-hydrogenation pathway available hypophosphorous acid derivatives. Further investigation into allylation mechanism provided access analogy acetate−allylic phosphinate, which then led development of a Pd-catalyzed rearrangement preformed phosphinates esters and, ultimately, dehydrative alcohols. disclosed herein constitute efficient synthetic approaches, not only prepare H-phosphinic acids but also their via one-pot tandem processes. In addition, potential H-phosphinates as useful synthons for preparation other organophosphorus demonstrated.