A Simple, Efficient, and Green Procedure for the 1,4-Addition of Thiols to Conjugated Alkenes and Alkynes Catalyzed by Sodium Acetate in Aqueous Medium
作者:Brindaban C. Ranu、Tanmay Mandal
DOI:10.1071/ch06455
日期:——
A benign and inexpensive salt, sodium acetate, efficiently catalyzes 1,4-addition of thiols to a variety of conjugated alkenes such as α,β-unsaturatedketones, aldehydes, carboxylic esters, nitriles, nitro compounds, and chalcones in aqueous THF. The reactions are clean, fast, and high yielding.
Ionic liquid as catalyst and solvent: the remarkable effect of a basic ionic liquid, [bmIm]OH on Michael addition and alkylation of active methylene compounds
作者:Brindaban C. Ranu、Subhash Banerjee、Ranjan Jana
DOI:10.1016/j.tet.2006.10.077
日期:2007.1
ketones, carboxylic esters and nitriles. It further catalyzes the addition of thiols to α,β-acetylenic ketones and alkylation of 1,3-dicarbonyl and -dicyano compounds. The Michael addition to α,β-unsaturated ketones proceeds in the usual way, giving the monoaddition products, whereas addition to α,β-unsaturated esters and nitriles leads exclusively to the bis-addition products. The α,β-acetylenic ketones
Dithianes are versatile umpolung intermediates in organic synthesis but have rarely been employed in radical cross-coupling reactions. Here we describe the oxidative coupling method for alkynedifunctionalization under metal-catalyst-free conditions. The efficient protocol directly affords a variety of β-ketodithianes in good to excellent yields with high regioselectivities. It provides a general pathway
Oxidative Generation of Thioalkyl Cations from 2-Tributylstannyl-1,3-dithianes and 1-(Tributylstannyl)alkyl Sulfides and Their Reactions with Olefinic Nucleophiles
作者:Koichi Narasaka、Noriyoshi Arai、Tatsuo Okauchi
DOI:10.1246/bcsj.66.2995
日期:1993.10
2-Tributylstannyl-1,3-dithianes and 1-(tributylstannyl)alkyl sulfides are oxidized with ammoniumhexanitratocerate(IV) or ferrocenium hexafluorophosphate to generate their cation radicals, which dissociate into the carbocations and tributylstannyl radical. The carbocations thus generated react with olefinic nucleophiles to afford the corresponding addition products in good yield.