The carboxyl group (COOH) is an omnipresent functional group in organic molecules, and its direct catalytic activation represents an attractive synthetic method. Herein, we describe the first example of a direct catalytic nucleophilic activation of carboxylicacids with BH3·SMe2, after which the acids are able to act as carbon nucleophiles, i.e. enolates, in Mannich-type reactions. This reaction proceeds
Siloxy Esters as Traceless Activators of Carboxylic Acids: Boron‐Catalyzed Chemoselective Asymmetric Aldol Reaction**
作者:Taiki Fujita、Mina Yamane、W. M. C. Sameera、Harunobu Mitsunuma、Motomu Kanai
DOI:10.1002/anie.202109788
日期:2021.11.8
We developed a chiral boron-catalyzed, carboxylic acid-selective asymmetric aldol reaction applicable to multifunctional substrates at late stages for the first time. Computational studies rationalized the reaction mechanism and stereoselectivity through Si/B enediolates acting as the active species.
Asymmetric Synthesis of New Chiral β-Amino Acid Derivatives by Mannich-type Reactions of Chiral <i>N</i>-Sulfinyl Imidates with <i>N</i>-Tosyl Aldimines
作者:Filip Colpaert、Sven Mangelinckx、Norbert De Kimpe
DOI:10.1021/ol100073y
日期:2010.5.7
New chiral β-(sulfonylamino)sulfinylimidates are synthesized in high overall yield and excellent diastereomeric excess via highly anti-selective Mannich-type reactions of chiral N-tert-butanesulfinyl imidates with N-tosyl aldimines. Deprotection of the β-(sulfonylamino)sulfinylimidates gave access to enantiopure imidate hydrochlorides in high yields, as useful intermediates for an easy transformation