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Active Site Design in a Chemzyme: Development of a Highly Asymmetric and Remarkably Temperature‐Independent Catalyst for the Imino Aldol Reaction
Author(s) -
Xue Song,
Yu Su,
Deng Yonghong,
Wulff William D.
Publication year - 2001
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/1521-3773(20010618)40:12<2271::aid-anie2271>3.0.co;2-n
Subject(s) - aldol reaction , catalysis , trimethylsilyl , chemistry , substituent , ligand (biochemistry) , catalytic cycle , zirconium , phenol , medicinal chemistry , combinatorial chemistry , organic chemistry , biochemistry , receptor
Unusually robust : A remarkably temperature‐independent catalyst has been developed for the imino aldol reaction of imines derived from ortho ‐aminophenols (see scheme). This catalyst is prepared from two equivalents of the VAPOL ligand and a zirconium tetraalkoxide. From a consideration of likely intermediates in the catalytic cycle it was deduced that a methyl substituent ortho to the phenol (R 1 ) should enhance induction. This resulted in asymmetric inductions in excess of 98 % ee at room temperature as well as at 100°C. TMS=trimethylsilyl.