¹³C chemical shift non‐equivalence in methylene carbons of monosubstituted cyclohexanes

Abstract

Monosubstituted cyclohexanes were synthesized by addition of a cyclohexyl radical to olefins bearing different substituents at the α‐position. Six distinct methylene 13C resonances were observed, indicating that the methylene carbons located at the 2 and 6 positions and at the 3 and 5 positions are not magnetically equivalent. This magnetic non‐equivalence (anisochronism) observed in the monosubstituted cyclohexanes is due to the introduction of an asymmetric center β to the prochiral C‐1 ring carbon. Copyright © 1989 John Wiley & Sons, Ltd.