γ-disubstituted propargylic tosylates was achieved by using metallic barium as the promoter. Various propargylated hydrazines (α-adducts) were exclusively synthesized from the corresponding propargylic tosylates and azobenzenes (diaryldiazenes). The thus-obtained propargylic hydrazines were further efficiently converted into propargylicamines by reductive N–N bond cleavage. Benzidine rearrangement of the propargylic
Selective Propargylation of Azo Compounds with Barium Reagents
作者:Akira Yanagisawa、Takanori Koide、Kazuhiro Yoshida
DOI:10.1055/s-0029-1219944
日期:2010.6
A Barbier-type propargylation of azo compounds with γ-trialkylsilylated propargylic bromides has been achieved using reactive barium as a low-valent metal in THF. Corresponding propargylated hydrazines (α-adducts) were exclusively formed not only from azobenzenes (diaryldiazenes) but also from dialkyl azodicarboxylates. This method is also applicable to γ-alkylated or γ-phenylated propargylic bromides
Cr-Catalyzed Regio-, Diastereo-, and Enantioselective Reductive Couplings of Ketones and Propargyl Halides
作者:Xiaochong Guo、Zhaoxin Shi、Feng-Hua Zhang、Zhaobin Wang
DOI:10.1021/acscatal.3c00177
日期:2023.3.3
reactivity and stereoselectivitycontrol. Herein, we developed the Cr-catalyzed asymmetric reductive coupling of racemic propargylic chlorides and ketones, affording valuable chiral tertiary alcohols bearing vicinal stereocenters. These reactions proceed efficiently under mild conditions in a radical–polar crossover manner with good regio-, diastereo-, and enantioselectivity control. Preliminary mechanistic