Chemoselective deprotection and deprotection with concomitant reduction of 1,3-dioxolanes, acetals and ketals using nickel boride
作者:Jitender M. Khurana、Kiran Dawra、Purnima Sharma
DOI:10.1039/c4ra15404e
日期:——
An efficient and mild methodology for the reductive deprotection of 1,3-dioxolanes, acetals and ketals to the corresponding aldehydes/ketones and also deprotection with concomitant reduction to the corresponding alcohols has been achieved in quantitative yields using nickel boride generated in situ from nickel chloride and sodium borohydride in methanol. The reactions are chemoselective as halo, alkoxy
New Applications of Solid Silica Chloride (SiO 2 -Cl) in Organic Synthesis. Efficient Preparation of Diacetals of 2,2-Bis(Hydroxymethyl)-1,3-propanediol from Different Substrates and Their Transthioacetalization Reactions. Efficient Regeneration of Carbonyl Compounds from Acetals and Acylals
application of solid silica chloride, an easily available and efficient catalyst for the preparation of diacetal of 2,2-bis-(hydroxymethyl)-1,3-propanediol from aldehydes, acetals, acylals, and oximes, is described. Transthioacetalization of diacetals of 2,2-bis-(hydroxymethyl)-1,3-propanediol into their corresponding 1,3-dithianes and 1,3-dithiolanes in the presence of silica chloride is presented. Efficient
Novel Preparation of α,β-Unsaturated Aldehydes. Benzeneselenolate Promotes Elimination of HBr from α-Bromoacetals
作者:Andrei Vasil'ev、Lars Engman
DOI:10.1021/jo9917644
日期:2000.4.1
elimination/hydrolysis of these mixtures afforded alpha,beta-unsaturated aldehydes in 50-80% overall yields. In the case of tertiary alpha-bromoacetals, treatment with benzeneselenolate afforded only dehydrobromination products as mixtures of isomers. The presence of at least a catalytic amount of the organoselenium reagent was found to be crucial for olefin formation. A SET-mechanism, involving benzeneselenolate-induced
Regioselective transformation of alkynes into cyclic acetals and thioacetals with a gold(I) catalyst: comparison with Brønsted acid catalysts
作者:Laura L. Santos、Violeta R. Ruiz、Maria J. Sabater、Avelino Corma
DOI:10.1016/j.tet.2008.06.032
日期:2008.8
Au(I) catalyzes the transformation of alkynes into cyclic acetals and thioacetals at much higher rate than Brønsted acids. The reaction appears to be general for a range of alkynes and diols or dithiols, which are efficiently transformed with high selectivities. One of the salient features of this reaction process is the high reactivity of the enol ether or enol thioether intermediates, which undergo
Reaction of 2-alkyl-2-phenyl-1,3-dioxolans with iodine monochloride: formation of α-phenylalkanoate esters
作者:André Goosen、Cedric W. McCleland
DOI:10.1039/c39820001311
日期:——
2-Alkyl-2-phenyl-1,3-dioxolans undergo a high-yield transformation into 2-chloroethyl α-phenylalkanoates upon treatment with iodinemonochloride in dichloromethane.