Ketenimine-nitrile rearrangements of N-alkoxyketenimines under their generation conditions
摘要:
C,C-Substituted N-ethoxyketenimines are extremely unstable even under their generation conditions (dehydrochlorination of N-ethoxyimidoyl chlorides, dehalogenation of alpha-bromo-N-ethoxyimidoyl halides, the reaction of methylmethoxycarbonylketene with N-ethoxytriphenylphosphinimine) undergo two types of rearrangements: synchronous ring decomposition down to acetaldehyde and the corresponding CH-nitrile and 1,3-migration of the EtO group with formation of alpha-ethoxynitriles. We suggest that the instability of N-alkoxyketenimines is mainly due to weakening of the NO bond as a result of pi(CC)-sigma(NO)* hyperconjugation.
Ketenimine-nitrile rearrangements of N-alkoxyketenimines under their generation conditions
摘要:
C,C-Substituted N-ethoxyketenimines are extremely unstable even under their generation conditions (dehydrochlorination of N-ethoxyimidoyl chlorides, dehalogenation of alpha-bromo-N-ethoxyimidoyl halides, the reaction of methylmethoxycarbonylketene with N-ethoxytriphenylphosphinimine) undergo two types of rearrangements: synchronous ring decomposition down to acetaldehyde and the corresponding CH-nitrile and 1,3-migration of the EtO group with formation of alpha-ethoxynitriles. We suggest that the instability of N-alkoxyketenimines is mainly due to weakening of the NO bond as a result of pi(CC)-sigma(NO)* hyperconjugation.