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Three‐Component Asymmetric Catalytic Ugi Reaction—Concinnity from Diversity by Substrate‐Mediated Catalyst Assembly
Author(s) -
Zhao Wenjun,
Huang Li,
Guan Yong,
Wulff William D.
Publication year - 2014
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201310491
Subject(s) - catalysis , iminium , chemistry , aldehyde , amine gas treating , substrate (aquarium) , phenol , organocatalysis , combinatorial chemistry , ugi reaction , ligand (biochemistry) , organic chemistry , enantioselective synthesis , isocyanide , biochemistry , oceanography , receptor , geology
The first chiral catalyst for the three‐component Ugi reaction was identified as a result of a screen of a large set of different BOROX catalysts. The BOROX catalysts were assembled in situ from a chiral biaryl ligand, an amine, water, BH 3 ⋅SMe 2 , and an alcohol or phenol. The catalyst screen included 13 different ligands, 12 amines, and 47 alcohols or phenols. The optimal catalyst system (LAP 8‐5‐47) provided α‐amino amides from an aldehyde, a secondary amine, and an isonitrile with excellent asymmetric induction. The catalytically active species is proposed to be an ion pair that consists of the chiral boroxinate anion and an iminium cation.