Reactions of diphenylcyclopropenone with trivalent phosphorus compounds.

Abstract

Diphenylcyclopropenone (1) reacted readily with trivalent phosphorus compounds (2a-e) to afford the new type of phosphoranes, ketene-phosphoranes (4a-e). These ketene-phosphoranes as intermediates further reacted with 1 to give five-membered unsaturated lactone derivatives (9, 15) or rearranged to the novel phosphine (13). The ketene-phosphorane (4a) derived from 1 and triphenylphosphine (2a) is the first example of the isolated phosphorane possessing the ketene group in a molecule, whose efficiency for the synthesis of cinnamic acid derivatives and the cyclobutenedione derivative is attractive.