Download PDF
Synlett 2005(9): 1459-1461  
DOI: 10.1055/s-2005-868510
LETTER
© Georg Thieme Verlag Stuttgart · New York

Direct Formation of Synthetically Useful Silyl-Protected Aldol Adducts via the Asymmetric Reductive Aldol Reaction

Nathan O. Fuller, James P. Morken*
Department of Chemistry, Venable and Kenan Laboratories, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, USA
Fax: +1(919)9622388; e-Mail: morken@unc.edu;
Further Information

Publication History

Received 28 February 2005
Publication Date:
29 April 2005 (online)

    Permissions and Reprints All articles of this category

Abstract

Examination of different silane reducing agents in the reductive aldol reaction revealed that Me2 i-PrSiH is highly selective for formation of the silylated aldol adduct versus the derived acylated adduct. This silicon group provides more robust protection for the product β-hydroxyl group than the diethylmethylsilyl group, which was employed previously.

Key words

asymmetric synthesis - asymmetric catalysis - hydro­silylations - protecting groups - aldol reactions

9

General Procedure.
An oven-dried 2-dram vial was charged with 0.006 mmol of [(cod)RhCl]2 and 0.016 mmol of (R)-BINAP in 400 µL of dry 1,2-dichloroethane. The catalyst solution was stirred for 1 h and then 1.25 mmol of Et2MeSiH was added. After stirring 30 min, an additional 100 µL of 1,2-dichloroethane was added, followed by 0.30 mmol of phenyl acrylate and 0.25 mmol of butyraldehyde. The vial was sealed and the mixture was allowed to stir for 24 h at r.t. After 24 h, the solvent was evaporated and the crude mixture was purified via flash column chromatography to provide the expected silyl ether.