Synthesis of a <i>C</i><sub>2</sub>-Symmetric Chiral Borinic Acid and Its Application in Catalytic Desymmetrization of 2,2-Disubstituted-1,3-Propanediols
作者:Jian Song、Wen-Hua Zheng
DOI:10.1021/jacs.3c02331
日期:——
synthesis of efficient chiral boronic acids remains a formidable challenge. Herein we disclose a rational design and a concise synthesis of a series of novel C2-symmetric disubstituted boronic acids, or borinic acids. Chiral borinic acids have been found to be excellent agents that can achieve highly enantioselective desymmetrization of 2,2-disubstituted-1,3-propanediols, providing chiral diols with a quaternary
Tricarbonylchromium complexes 1 react with monosubstituted malonic acid esters 2 in DMSO at room temperature in the presence of KOtBu to give the complexes 3. After oxidative demetalation, the appropriate aryl derivatives 4 are obtained in moderate to good overall yields. Diastereoselective arylations of chirally modified malonates such as 5a-c were studied. The stereoselectivity was highest for the products 6c/6c' (80:20) with (-)-8-phenylmenthol as alcohol component in the malonate 5.
Substrate specificity of an esterase from the archaeon<i>Sulfolobus tokodaii</i>bearing a GGG(A)X motif
A GGG(A)X-type esterase (Est0071) from an archaeon catalyzes asymmetric hydrolysis of prochiral bulky malonic diesters in good enantioselectivity. The selectivity of Est0071 was for the opposite enantiomer to that previously shown for pig liver esterase, and the resulting enantiomeric excess of the products was higher. Est0071 could also catalyze the hydrolysis of various acetates of secondary alcohols, and showed moderate enantioselectivity in these reactions.
Piorko, Adam; Abd-El-Aziz, Alaa S.; Lee, Choi Chuck, Journal of the Chemical Society. Perkin transactions I, 1989, p. 469 - 475
作者:Piorko, Adam、Abd-El-Aziz, Alaa S.、Lee, Choi Chuck、Sutherland, Ronald G.