The selective properties of the fungus Aureobasidium pullulans, in the antifungal agent Boni Protect, were investigated in the fermentative bioreduction of selected carbonyl compounds. Catalyzed by oxidoreductases contained in the microorganism Aureobasidium pullulans highly enantioselective biotransformation of prochiral ketones provides the secondary alcohols when the reaction is done in the presence
Asymmetric catalytic arylation of ethyl glyoxylate using organoboron reagents and Rh(i)–phosphane and phosphane–phosphite catalysts
作者:Carolina Silva Marques、Mehmet Dindaroğlu、Hans-Günther Schmalz、Anthony J. Burke
DOI:10.1039/c3ra47000h
日期:——
Herein we report the first application of Rh(I)–phosphane and phosphane–phosphite catalysts in the enantioselective catalyticarylation of ethyl glyoxylate with organoboronreagents, providing access to ethyl mandelate derivatives in high yield (up to 99%) and moderate to very good enantioselectivities (up to 75% ee). Commercial phosphane ligands, such as (R)-MonoPhos and (R)-Phanephos were tested
Steric and electronic effects in the enantioselective hydrogenation of activated ketones on platinum: Directing effect of ester group
作者:S DIEZI、S REIMANN、N BONALUMI、T MALLAT、A BAIKER
DOI:10.1016/j.jcat.2006.02.001
日期:2006.4.25
of the steric bulkiness of the α -ketoester. None of the mechanistic models developed for ketonehydrogenation on Pt are conform to the observations. Only additional steric effects in the modifiers and replacement of toluene by acetic acid as a reaction medium enhanced the sensitivity of the catalyst system to steric effects in the substrates (ee=0–94%ee=0–94%). An important mechanistic consequence
Dynamic Kinetic Resolution via Dual-Function Catalysis of Modified Cinchona Alkaloids: Asymmetric Synthesis of α-Hydroxy Carboxylic Acids
作者:Liang Tang、Li Deng
DOI:10.1021/ja0255047
日期:2002.3.1
dioxolanediones was realized via a modified cinchona alkaloid-catalyzed alcoholytic opening of the dioxolanedione ring, generating a variety of optically active alpha-hydroxy esters in 91-96% ee and 61-85% chemical yield. In this dynamic kinetic resolution, the modified cinchonaalkaloid was found to serve dual catalytic roles, mediating both the rapid racemization of the 5-aryl dioxolanediones and the enantioselective
A rapid and green approach to chiral α-hydroxy esters: asymmetric transfer hydrogenation (ATH) of α-keto esters in water by use of surfactants
作者:Lu Yin、Xian Jia、Xingshu Li、Albert S.C. Chan
DOI:10.1016/j.tetasy.2009.08.019
日期:2009.9
A series of α-hydroxyesters were rapidly prepared (1.5 h) from α-keto esters via asymmetrictransferhydrogenation (ATH) in water by the use of surfactants for the first time. This green method, catalyzed by a water-soluble and recyclable Ru(II) complex, gave moderate to high enantioselectivities (up to 99.7% ee) with DTAB as an additive and HCOONa as the hydrogen source.