Gold-Catalyzed One-Pot Synthesis of 1,3-Disubstituted Allenes from Benzaldehydes and Terminal Alkynes

Abstract

A new and facile one-pot synthesis of 1,3-disubstituted allenes, using cheap and readily available terminal alkynes, benzaldehyde derivatives and morpholine, was developed. A small library of 20 allenes demonstrates a broad applicability, with yields up to 86%. Isotopic-labelling and cross-over experiments strongly indicate that our reaction proceeds via a two-step A3-coupling followed by a 1,5-hydrogen shift process. (Figure presented.).