Catalytic Asymmetric Access to Noncanonical Chiral α-Amino Acids from Cyclic Iminoglyoxylates and Enamides
作者:Yue Zhang、Jun-Kuan Li、Fa-Guang Zhang、Jun-An Ma
DOI:10.1021/acs.joc.0c00436
日期:2020.4.17
Mannich reaction of cyclic iminoglyoxylates with enamides by virtue of chiral phosphoric acid catalysis in a one-pot manner. The wide substrate scope, mild reaction conditions, and constantly excellent enantioselectivities (>95% ee in most cases) render this protocol highly practical for the rapid construction of valuable noncanonical chiral α-amino-acid building blocks.
An Achiral-Acid-Induced Switch in the Enantioselectivity of a Chiral cis-Diamine-Based Organocatalyst for Asymmetric Aldol and Mannich Reactions
作者:Shin A. Moteki、Jianwei Han、Satoru Arimitsu、Matsujiro Akakura、Keiji Nakayama、Keiji Maruoka
DOI:10.1002/anie.201107239
日期:2012.1.27
Pick and choose: The asymmetric synthesis of two different enantiomeric products has been achieved through the use of a single organocatalyst with or without achiral organic acid additives (see scheme). These additives may assist in altering the substrate orientations at the catalytic center, leading to efficient enantiomeric inversions in both aldol and Mannich products.