Strong hyperconjugative interactions limit solvent and substituent influence on conformational equilibrium: the case of cis-2-halocyclohexylamines.

ABSTRACT: The presence of strong stereoelectronic interactions involving the substituents in cis-2-substituted cyclohexanes may lead to results different from those expected. In this work, we studied the conformational behavior of cis-2-fluoro- (F), cis-2-chloro- (Cl), cis-2-bromo- (Br) and cis-2-iodocyclohexylamine (I) by dynamic NMR and theoretical calculations. The experimental data pointed to an equilibrium strongly shifted toward the ea conformer (equatorial amine group and axial halogen), with populations greater than 90% for F, Cl and Br in both dichloromethane-d ₂ and methanol-d ₄. Theoretical calculations (M06-2X/6-311++G(2df,2p)) were in agreement with the experime

SUBMITTER: Francisco CB 

PROVIDER: S-EPMC6466766 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature