Direct Estimate of the Conjugative and Hyperconjugative Stabilization in Diynes, Dienes, and Related Compounds

Abstract

The intrinsic strength of the conjugation and hyperconjugation in 1,3‐butadiene, 1,3‐butadiyne, and related compounds was determined by energy decomposition analysis. The calculations indicate that the π conjugation in 1,3‐butadiyne is roughly twice as strong as that in 1,3‐butadiene, and that the hyperconjugative interactions of CH and CC bonds with CC multiple bonds are about half as strong as the π conjugation between multiple bonds.