Reagent-controlled enantioselectivity switch for the asymmetric fluorination of β-ketocarbonyls by chiral primary amine catalysis
作者:Yang'en You、Long Zhang、Sanzhong Luo
DOI:10.1039/c6sc03109a
日期:——
enantioselectivity switch was uncovered in the asymmetric α-fluorination of β-ketocarbonyls by a chiral primary amine catalyst. By a simple swap of fluorination reagents, both enantiomers of the quaternary fluorination adducts could be obtained with good yields and high enantioselectivity. Mechanistic studies disclosed dual H-bonding and electrostatic stereocontrolling modes for the catalysis.
A facile and efficient one-pot synthesis of polysubstituted pyridin-2(1H)-ones from a variety of beta-oxo amides underVilsmeierconditions is described, and a mechanism involving sequential halogenation, formylation and intramolecular nucleophilic cyclization is proposed.
The Preparation and Cyclization of Substituted Acetoacetanilides
作者:A. Langley Searles、Richard J. Kelly
DOI:10.1021/ja01627a095
日期:1955.11
Copolymerizable azo compounds and articles containing them
申请人:Pearson Jason Clay
公开号:US20080182957A1
公开(公告)日:2008-07-31
Polymerizable light absorbing azo dyes are disclosed useful as monomers in the formation of devices such as, but not limited to ocular lenses. Specifically, intraocular lenses (IOL) are disclosed wherein one or more of the light absorbing dye is covalently bonded to other structural polymers though ethylene unsaturated groups. The resulting IOLs possess light absorbing properties without significant amounts of free (un-bound) azo dye molecules present in the final structural polymer matrix.