Cobalt(II)-Catalyzed Conversion of Allylic Alcohols/Acetates to Allylic Amides in the Presence of Nitriles
摘要:
Various secondary allylic alcohols or their acetates and tertiary allylic alcohols can be converted to the corresponding transposed allylic amides in the presence of a catalytic quantity of cobalt(II) chloride and acetic anhydride in acetonitrile. Tertiary alcohols undergo complete rearrangement whereas secondary ones afford a mixture of regioisomers. Moderate yields of amides are also obtained by reacting acrylonitrile with secondary alcohols in 1,2-dichloroethane. The presence of acetic anhydride or acetic acid is crucial to the formation of amides as the absence of the former affords no amides and the allylic alcohols are mainly recovered as regioisomeric mixtures. The regioselectivity during amide formation can be enhanced by using cobalt complexes 14-16 in acetic acid medium. Some preliminary studies indicate that these reactions are proceeding via an pi-allyl complex or tight ion pair rather than a [3,3] sigmatropic rearrangement of acetamidate obtained in a Pinner reaction.
Conjugate addition of methyl groups of αβ-unsaturated aldehydes: use of Me<sub>5</sub>Cu<sub>3</sub>Li<sub>2</sub>
作者:Derrick L. J. Clive、Vittorio Farina、Pierre Beaulieu
DOI:10.1039/c39810000643
日期:——
Me5Cu3Li2 converts αβ-unsaturated aldehydes efficiently into β-methyl aldehydes and, unlike Me2CuLi, it usually gives a negligible amount of the 1,2-adduct even when a quaternary carbon is generated in the reaction.