Baker's yeast mediated reduction of dihydroxyacetone derivatives
摘要:
Several monoprotected dihydroxyacetone derivatives 4a-d and their acetates 5a-d were prepared and subjected to biotransformation with baker's yeast. The simple chemical modification of the substrates (i.e. transforming the relatively small hydrophilic hydroxymethyl group into a larger hydrophobic acetoxymethyl moiety) inverted the sense of enantiotope selectivity of these reductions yielding optically active diols 6a-d, or their enantiomeric acetates (7a-d) and diols (ent-6a-d), respectively. (C) 1999 Elsevier Science Ltd. All rights reserved.
I<sub>2</sub>-Catalyzed Regioselective Oxo- and Hydroxy-acyloxylation of Alkenes and Enol Ethers: A Facile Access to α-Acyloxyketones, Esters, and Diol Derivatives
作者:Rambabu N. Reddi、Pragati K. Prasad、Arumugam Sudalai
DOI:10.1021/ol5027393
日期:2014.11.7
I-2-catalyzed oxo-acyloxylation of alkenes and enol ethers with carboxylic acids providing for the high yield synthesis of a-acyloxyketones and esters is described. This unprecedented regioselective oxidative process employs TBHP and Et3N in stoichiometric amounts under metal-free conditions in DMSO as solvent. Additionally, I-2-catalysis allows the direct hydroxy-acyloxylation of alkenes with the sequential addition of BH3 center dot SMe2 leading to monoprotected diol derivatives in excellent yields.