Asymmetric Michael addition reactions of pyrrolones with chalcones catalyzed by vicinal primary-diamine salts
作者:Xiaolei Du、Dawei Yin、Zemei Ge、Xin Wang、Runtao Li
DOI:10.1039/c7ra03069j
日期:——
The efficient asymmetric Michael addition reactions of pyrrolones with chalcones catalyzed by a simple and commercially available chiral 1,2-diaminocyclohexane-2-(N-Boc-amino)benzoic acid have been developed to provide the corresponding Michael adducts in good yields (up to 90%) and high enantioselectivities (up to 95% ee).
a (ZhaoPhos) catalytic system has been identified for the straightforward asymmetric synthesis of chiral γ-lactams. A variety of NH free α,β-unsaturated lactams bearing a β-aryl or β-alkyl substituent were smoothly hydrogenated to provide the desired γ-lactams in up to 99% yield and 99% enantiomeric excess (ee). This methodology provides a highly practical pathway to synthesize chiral γ-lactams or
Iron‐Catalyzed Carbenoid‐Transfer Reactions of Vinyl Sulfoxonium Ylides: An Experimental and Computational Study
作者:Janakiram Vaitla、Annette Bayer、Kathrin H. Hopmann
DOI:10.1002/anie.201810451
日期:2018.12.3
the generation of unprecedented vinyl carbenoids from sulfoxonium ylides has been developed and applied in the synthesis of a diverse array of heterocycles such as indolizines, pyrroles, 3‐pyrrolin‐2‐ones, and furans. The reactions proceed by FeBr2 catalysis under mild reaction conditions with a broad substrate scope. A reaction pathway involving iron carbenoids is proposed based on a series of control
carboxylic acids (acid iteration sequence) in one direction and the sequential addition of the carboxylic acids to the vinyl sulfoxonium ylide (ylide iteration sequence) in another direction yield (Z)-configured unsaturated oligoesters. To perform this iteration, we have developed a highly regioselective insertion of vinyl sulfoxonium ylide into the X–H (X = O, N, C, S, halogen) bond of acids, thiols