Catalytic asymmetric epoxidation of alkenes with arabinose-derived uloses
作者:Tony K.M Shing、Yiu C Leung、Kwan W Yeung
DOI:10.1016/s0040-4020(03)00145-5
日期:2003.3
Four l-erythro-2-uloses were readily prepared from l-arabinose via a reaction sequenceinvolving Fischer glycosidation, acetalization and oxidation. Bulky steric sensors at the anomeric center could enhance the stereoselectivity of the dioxirane epoxidation and one of the uloses performed with good enantioselectivity towards trans-stilbene (up to 90% ee). However, the catalysts decomposed during the
visible-light-induced aerobic oxidative [2 + 3] cycloaddition reaction between glycine derivatives and styreneoxides has been disclosed that provides an efficient approach for the rapid synthesis of 1,3-oxazolidines under mild conditions. This photoinduced process is enabled by the formation of an electron donor-acceptor complex between glycine derivatives and benzyl iodides.
Environmentally benign decarboxylative <i>N</i>-, <i>O</i>-, and <i>S</i>-acetylations and acylations
作者:Santanu Ghosh、Anisha Purkait、Chandan K. Jana
DOI:10.1039/d0gc03731a
日期:——
An operationally simple and general method for acetylation and acylation of a wide variety of substrates (amines, alcohols, phenols, thiols, and hydrazones) has been reported. Meldrum's acid and its derivatives have been used as an air-stable, non-volatile, cost-effective, and easy to handle acetylating/acylating agent. Easily separable byproducts (CO2 and acetone) allowed the isolation of analytically
Process for the ruthenium-catalysed epoxidation of olefins by means of hydrogen peroxide
申请人:Magerlein Wolfgang
公开号:US20060161011A1
公开(公告)日:2006-07-20
The present invention relates to a process for the epoxidation of olefins using catalysts based on ruthenium complexes in the presence of hydrogen peroxide.
P(RNCH<sub>2</sub>CH<sub>2</sub>)<sub>3</sub>N: Efficient Catalysts for Transesterifications, Acylations, and Deacylations
作者:Palanichamy Ilankumaran、J. G. Verkade
DOI:10.1021/jo981819m
日期:1999.4.1
Extremely strong nonionic superbases of the type P(RNCH(2)CH(2))(3)Ncatalyze the transesterification of carboxylic acid esters with high selectivity and yields at 25 degrees C. These bases also catalyze the deacetylation of alcohols undermildconditions in quantitative yields. Using enol acetates as acylating agents, primary and secondary alcohols are efficiently protected as acetates through the