13C Chemical shifts for 4-substituted phenylvinyl ethers, sulfides, and selenides: evidence concerning the relative abilities of O, S, and Se to transmit electronic effects

Abstract

13C chemical shifts for β carbons of 4-substituted phenylvinyl ethers, sulfides, and selenides plus previous data for styrenes indicate that the relative ability of link groups to transmit electronic effects between conjugative groups is S > Se ≈ — > O (where — refers to no link group, i.e. styrene). However, marked deviations from additivity are noted for C(1) chemical shifts which may indicate that O deactivates the ring to electronic substituent effects while S and Se activate the ring. If this explanation is valid then the actual ability of the link atom to transmit electronic effects is — > O > S > Se.