Phosphine-Catalyzed Difunctionalization of beta-Fluoroalkyl alpha,beta-Enones: A Direct Approach to beta-Amino alpha-Diazo Carbonyl Compounds

An efficient and practical phosphine-catalyzed vicinal difunctionalization of beta-fluoroalkyl alpha,beta-enones with TMSN3 has been developed. Using dppb as the catalyst, the reaction worked efficiently to yield various beta-amino alpha-diazocarbonyl compounds in high yields (up to 94%). This work marks the first efficient construction of alpha-diazocarbonyl compounds by phosphine catalysis. Meanwhile, the asymmetric variant induced by the nucleophilic bifunctional phosphine P4 led to various chiral fluoroalkylated beta-amino alpha-diazocarbonyl compounds in high yields and enantioselectivity. NMR and ESI-MS studies support the existence of the key reaction intermediates. In contrast, beta-azide carbonyl compounds would be furnished in good yields from beta-fluoroalkylated beta,beta-disubstituted enones.