Phosphine-mediated [2 + 2] cycloaddition of internal alk-2-ynoate and alk-2-ynone to [60]fullerene

Abstract

Treatment of RCH₂CCCOX with [60]fullerene in the presence of tricyclohexylphosphine (PCy₃) afforded a [2 + 2] cycloaddition product (1: R = H, X = OMe); 2: R = Bu, X = OMe; 3: R = X = Me which resulted from addition of the β, γ-carbons of RCH₂CCCOX to the carbon-carbon double bond across a 6/6 ring junction of [60]fullerene.