The Synthesis of Conformationally Restricted Analogs of Acetolactate
作者:William A. Kleschick、Liying S. Lu、Scott Thornburgh
DOI:10.1055/s-1997-1419
日期:1997.7
The synthesis of a conformationally restricted analog of acetolactate 1, a natural substrate for ketol acid reductoisomerase, is described. The key features of the successful synthesis are epoxidation of unsaturated ester 10 using urea-hydrogen peroxide complex and subsequent rearrangement of epoxide 11 to allylic alcohol 13 with aluminum tri-tert-butoxide. Compound 1 was neither a substrate for ketol acid reductoisomerase nor an inhibitor of the enzyme at concentrations up to 50 ppm.
Mild and efficient boronic acid catalysis of Diels–Alder cycloadditions to 2-alkynoic acids
作者:Hongchao Zheng、Dennis G. Hall
DOI:10.1016/j.tetlet.2010.04.132
日期:2010.7
The concept of boronic acid catalysis (BAC) for the activation of unsaturated carboxylic acids is applied to the Diels-Alder cycloaddition between 2-alkynoic acids as dienophiles and various dienes. These [4+2] cycloadditions produce cyclohexadienyl carboxylic acids, which can be oxidized in situ to produce polysubstituted aromatic carboxylic acids. The boronic acid catalyst is suspected to provide activation by a LUMO-lowering effect of the unsaturated carboxylic acid likely via a covalent, monoacylated hemiboronic ester intermediate. (C) 2010 Elsevier Ltd. All rights reserved.
Jones et al., Journal of the Chemical Society, 1956, p. 4073,4077
作者:Jones et al.
DOI:——
日期:——
Synthesis of half esters
申请人:Niwayama Satomi
公开号:US20090023945A1
公开(公告)日:2009-01-22
A method for hydrolyzing an ester is provided. In accordance with the method, a compound A is provided which has first and second ester moieties. The compound is reacted in a liquid medium with a base having the formula M
a
X
b
, such that the first ester moiety is converted to a carboxyl moiety and the second ester moiety remains, wherein the ratio [X
k−
]:[A] in the liquid medium is no greater than 1.6, and wherein k>0.