A thermal O-to-C [1,3]-rearrangement of α-hydroxy acid derived enol ethers was achieved under mild conditions. The 2-aminothiophenol protection of carboxylic acids facilitates formation of the [1,3] precursor and its thermalrearrangement via stabilization of a radical intermediate. Experimental and theoretical evidence for dissociative radical pair formation, its captodative stability via aminothiophenol
Addition of organomagnesium reagents to cyanohydrin--silyl ethers: An efficient and flexible synthesis of unsymmetrically substituted acyloins
作者:Melvyn Gill、Milton J Kiefel、Deborah A Lally
DOI:10.1016/s0040-4039(00)84415-9
日期:1986.1
Acyloins are prepared in high yields reaction between Grignard reagents and -trimethylsilyl ethers of aldehyde cyanohydrins: the method is particularly useful for the preparation of discrete acyloins in which the substituents are unsymmetrically disposed about the α-hydroxyketone moiety.
Enantioselective Aerobic Oxidation of α-Hydroxy-Ketones Catalyzed by Oxidovanadium(V) Methoxides Bearing Chiral, <i>N</i>-Salicylidene-<i>tert</i>-butylglycinates
作者:Chien-Tien Chen、Jun-Qi Kao、Santosh B. Salunke、Ya-Hui Lin
DOI:10.1021/ol1024053
日期:2011.1.7
Chiral oxidovanadium(V) methoxides prepared from 3,5-disubstituted-N-salicylidene-l-tert-butylglycines and vanadyl sulfate in air-saturated MeOH serve as highly enantioselective catalysts for asymmetric aerobic oxidations and kinetic resolution of alkyl, aryl, and heteroaryl α-hydroxy-ketones with differed α-substituents at ambient temperature in toluene or TBME (tert-butyl methyl ether). The best
Compositions and Methods for Fermentation of Biomass
申请人:Parekh Sarad
公开号:US20100268000A1
公开(公告)日:2010-10-21
In one aspect, this invention relates to production of useful fermentation end-products from biomass through simultaneous hydrolysis and fermentation by a microorganism, such as
Clostridium phytofermentans
. The invention also relates to the development of a process for efficient pretreatment and conversion of lignocellulosic biomass to end-products with high conversion efficiency (yield). In another aspect, methods for producing a fermentation end-product by fermenting hexose (C6) and pentose (C5) sugars with a microorganism, such as
Clostridium phytofermentans
are disclosed herein.
The thiaminediphosphate-dependent, branched-chain 2-keto aciddecarboxylase from Lactococcus lactis sup. cremoris B1157 (KdcA) is a new valuableenzyme for the synthesis of chiral 2-hydroxy ketones. The gene was cloned and the enzyme was expressed as an N-terminal hexahistidine fusion protein in Escherichia coli. It has a broad substrate range for the decarboxylation reaction including linear and