Synthesis 2011(2): 316-324  
DOI: 10.1055/s-0030-1258355
PAPER
© Georg Thieme Verlag Stuttgart ˙ New York

Asymmetric Reduction of α-Keto Aldoxime O-Ethers

Mariusz J. Bosiak*, Marcin M. Pakulski
Department of Chemistry, Nicolaus Copernicus University, 7 Gagarin Street, 87-100 Toruń, Poland
Fax: +48(56)6542477; e-Mail: bosiu@chem.umk.pl;
Further Information

Publication History

Received 22 September 2010
Publication Date:
07 December 2010 (online)

Abstract

The catalytic asymmetric reduction of α-keto aldoxime O-methyl, O-benzyl, and O-trityl ethers, derived from substituted acetophenones, with borane/oxazaborolidines, by transfer hydrogenation, and with yeast, was studied. The reduction with borane/oxazaborolidines produced the corresponding α-hydroxy oxime ethers, α-hydroxy hydroxylamine ethers, and β-amino alcohols in 39-78% yields and up to 77% ee. The carbonyl group was selectively reduced by transfer hydrogenation with formic acid-triethyl­amine catalyzed by RhCl[(R,R)-TsDPEN](C5Me5), and also with yeast, producing α-hydroxy oxime ethers, up to 75% ee and 93% ee, respectively.