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.
Cobalt(II) chloride catalysed conversion of allylic alcohols to rearranged allylic amides
作者:Naresh K. Nayyar、M. Madhava Reddy、Javed Iqbal
DOI:10.1016/0040-4039(91)80456-g
日期:1991.11
Secondary and tertiary allylic alcohols can be converted to the corresponding allylically rearranged amides and acetates in presence of a catalytic quantity of cobalt(II) chloride and acetic anhydride in acetonitrile. Tertiary alcohols undergo complete rearrangement whereas the secondary ones yield a mixture of regioisomers.
Co(III)DMG-Catalyzed Synthesis of Allylamides from Allyl Alcohols and Acetonitrile
作者:Manoj Mukhopadhyay、Javed Iqbal
DOI:10.1021/jo960557q
日期:1997.3.1
Cobalt(II)-Catalyzed Conversion of Allylic Alcohols/Acetates to Allylic Amides in the Presence of Nitriles
作者:Manoj Mukhopadhyay、M. Madhava Reddy、G. C. Maikap、Javed Iqbal
DOI:10.1021/jo00114a013
日期:1995.5
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.
Development of an Anomalous Heck Reaction: Skeletal Rearrangement of Divinyl and Enyne Carbinols
作者:J. Maina Ndungu、Kimberly K. Larson、Richmond Sarpong
DOI:10.1021/ol052382p
日期:2005.12.1
[reaction: see text] A general set of conditions that achieves the union of aryl halides and divinyl or enyne carbinols to afford tri- or tetrasubstituted olefins in good yields (up to 83%) is described. The mechanism by which this proceeds is believed to involve the intermediacy of a cyclopropanol, followed by a novel skeletal reorganization. The ability to suppress beta-hydride elimination of organopalladium