Stereochemical behavior of 1JCH and 2JCH NMR coupling constants in α-substituted acetamides

A rationalization of the stereochemical behavior of 1JCH and 2JCH coupling constants, involving nuclei in the vicinity of a carbonyl group were carried out in fluoroacetamide (1), chloroacetamide (2), bromoacetamide (3) and cyanoacetamide (4). 1JCH and 2JCH experimental and theoretically calculated coupling constant together with a qualitative analyses of hyperconjugative interactions through NBO data, showed that observed behavior is mainly due to the hyperconjugative interactions and electrostatic effects.