This Minireview provides insight into the early history of nucleophilic phosphinocatalysis. The concepts of 1,4-addition of a tertiary phosphine to an α,β-enone and of equilibrium between the resulting phosphonium zwitterion and phosphonium ylide established a fundamental basis for the development of several classical transformations, including the Rauhut-Currier, Morita, McClure-Baizer-Anderson, and Oda reactions.
Keywords: Lewis base; organocatalysis; phosphine catalysis; phosphonium ylide; phosphonium zwitterion.