Stereoselective Synthesis of Enamides by Pd-Catalyzed Hydroamidation of Electron Deficient Terminal Alkynes
摘要:
Hydroamidation of electron-deficient terminal alkynes by amides in presence of Pd catalyst has been exploited for the stereoselective synthesis of Z-enamides. The possible intramolecular hydrogen bonding between the amido proton and carbonyl oxygen of ester group provides the extra stability to the Z-isomer of vinyl palladium complex, which subsequently undergoes protodepalladation and leads to the Z-enamide selectively. This process is found to be mild and operationally simple with broad substrate scope.
Stereoselective Synthesis of Enamides by Pd-Catalyzed Hydroamidation of Electron Deficient Terminal Alkynes
作者:Niranjan Panda、Raghavender Mothkuri
DOI:10.1021/jo301772f
日期:2012.10.19
Hydroamidation of electron-deficient terminal alkynes by amides in presence of Pd catalyst has been exploited for the stereoselective synthesis of Z-enamides. The possible intramolecular hydrogen bonding between the amido proton and carbonyl oxygen of ester group provides the extra stability to the Z-isomer of vinyl palladium complex, which subsequently undergoes protodepalladation and leads to the Z-enamide selectively. This process is found to be mild and operationally simple with broad substrate scope.
Stereoselective Chlorination and Bromination of Enamides and Enamines via an Electrostatic Attraction Effect Using (1,1-Diacetoxyiodo)benzene and a Halide Source
作者:Linlin Xing、Chunbao Li
DOI:10.1021/acs.joc.5b01603
日期:2015.10.16
structure of the intermediates, the conformations of which are controlled by the electrostatic attractions between the positively charged nitrogen atoms and the oxygen atoms of the carbonyl group. This type of electrostatic effect has never been reported in olefin halogenations. For this reason, the three-membered bromoniumion is only a minor intermediate in the enamine bromination pathway. These methods