Highly Efficient Synthesis of Allenes from Trimethylaluminum Reagent and Propargyl Acetates Mediated by a Palladium Catalyst

A series of propargyl acetates were prepared and used as propargyl electrophiles for coupling reactions with trimethylaluminum. The simple catalytic system of palladium(II) acetate (1 mol‐%) and tri( o ‐tolyl)phosphine (2 mol‐%) worked efficiently for a wide variety of aromatic and aliphatic propargyl acetates, producing the substituted allenes in good to excellent yields of up to 94 % in tetrahydrofuran. The process was simple and easily performed, and it provides an efficient method for the synthesis of substituted allene derivatives. On the basis of the experimental results, a possible catalytic cycle has been proposed.