Kinetic Resolution of Racemic 1-Heteroarylalkanols by Asymmetric Esterification Using Diphenylacetic Acid with Pivalic Anhydride and a Chiral Acyl-transfer Catalyst
作者:Isamu Shiina、Keisuke Ono、Kenya Nakata
DOI:10.1246/cl.2011.147
日期:2011.2.5
A variety of optically active 1-heteroarylalkanols and their esters, which include heteroaromatic moieties, such as 2-furyl, 2-thienyl, 3-thienyl, 2-thiazoyl, 2-benzothiazoyl, and 2-benzoxazoyl gro...
Stereoselective reduction of chiral 3-(p-tolylsulfinyl)-2-thienyl ketones with diisobutylaluminum hydride (DIBAL) or lithium tri-sec-butylborohydride (L-Selectride) has been achieved. Reduction of the ketones with DIBAL in the presence of a Lewis acid or with L-Selectride afforded predominantly the thienyl carbinols, while the reduction with DIBAL alone gave the other diastereoisomeric alcohols as the major product. This method has been successfully applied to an efficient route to chiral thienyl alcohols.
An efficient iridiumcatalyst composed of a simple and commercially available o-methoxytriphenylphosphine and 9-Amino (9-deoxy) epi-cinchonine was applied to the asymmetric hydrogenation of heteroaromatic ketones. A range of simple heteroaromatic ketones could be hydrogenated with good to excellent enantioselectivities and high activities. In particular, thiophene ketones and furyl ketones furnished