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Ultrasound‐Promoted Enantioselective Decarboxylative Protonation of α‐Aminomalonate Hemiesters by Chiral Squaramides: A Practical Approach to Both Enantiomers of α‐Amino Esters
Author(s) -
Some Surajit,
Kim Han Yong Bae, Mun Jong,
Zhang Yong Jian,
Song Choong Eui
Publication year - 2017
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201700786
Subject(s) - enantioselective synthesis , chemistry , squaramide , enantiomer , protonation , cinchona , organocatalysis , organic chemistry , cinchonidine , catalysis , ion
Herein, we report an ultrasound‐promoted enantioselective decarboxylative protonation reaction of α‐aminomalonate hemiesters 1 in the presence of chiral cinchona‐derived squaramide Brønsted bases under mild conditions, which afforded both the ( S )‐ and ( R )‐enantiomers of α‐amino acid derivatives 2 in excellent yields (> 90 %) and excellent enantioselectivities (up to 98 % ee ).