pi-Strain-induced electrophilicity in small cycloalkynes: A DFT analysis of the polar cycloaddition of cyclopentyne towards enol ethers

Abstract

Small cycloalkynes possess a pi-strain-induced electrophilicity related to the bending of the C-SP3-C-SP-C-SP bond angle. For cyclopentyne and benzyne, the electrophilicity index defined in the context of density functional theory gives a coherent rationale for the reactivity of these cycloalkynes, which may act as electrophiles in polar cycloaddition. reactions toward enol ethers.