4-Hydroxyphenylglycine-Based Oxazaborolidines for Enantioselective Reductions of Ketones
作者:Manfred Braun、Michael Sigloch、Jens Cremer
DOI:10.1002/adsc.200600297
日期:2007.2.5
Amino alcohols 6 featuring the diphenylhydroxymethyl group are prepared from the commercial amino acid (R)-4-hydroxyphenylglycine 3. Oxazaborolidines generated in situ from the amino alcohols 6 and borane-dimethylsulfide serve as catalysts in enantioselective reductions of acetophenone. The para-substituents of the phenyl ring at the stereogenic carbon atom have a substantial influence on the enantioselectivity
Synthesis of Heavily Substituted 1,2-Amino Alcohols in Enantiomerically Pure Form
作者:Noemí García-Delgado、Katamreddy Subba Reddy、Lluís Solà、Antoni Riera、Miquel A. Pericàs、Xavier Verdaguer
DOI:10.1021/jo050960+
日期:2005.9.1
simple and convenient methodology for the preparation of optically pure 2-amino-2-aryl-1,1-diphenylethanols is presented. Allylamine was found to produce the ring-opening of triaryloxiranes in a regioselective and a stereospecific fashion. Removal of the allyl protecting group provided the free 1,2-amino alcohols in enantiomericallypure form.