Regiocontrolled Formation of 4,5-Dihydro-3(2<i>H</i>)-furanones from 2-Butyne-1,4-diol Derivatives. Synthesis of Bullatenone and Geiparvarin
作者:Hiroyuki Saimoto、Tamejiro Hiyama、Hitosi Nozaki
DOI:10.1246/bcsj.56.3078
日期:1983.10
Two new methods for selective hydration of 1,1,4-trisubstituted 2-butyne-1,4-diols (1) to give 4,5-dihydro-3(2H)-furanone derivatives are reported. The first involves selective monoacetylation of the less hindered hydroxyl group of 1 followed by Ag(I)-catalyzed rearrangement and cyclization to give 3-acetoxy-2,2,5-trisubstituted 2,5-dihydrofurans (2). Final hydrolysis yielded 2,2,5-trisubstituted 4
Synthesis of Enantiomerically Enriched 2,5-Dihydrofuran Derivatives from Easily Available Enantiomerically Enriched 2-Butyne-1,4-diols by Stereospecific Transformation
The transformation of enantiomericallyenriched 1,1,4-trisubstituted 4-acyloxy-2-butyn-1-ols 3 into 2,2,5-trisubstituted 3-acyloxy-2,5-dihydrofurans 5 with complete stereospecificity was achieved by an Ag(I)-mediated rearrangement of the monoesters 3 to allenic intermediates 4, followed by Ag(I)-assisted cyclization. A stereochemical analysis revealed that the newly formed carbon–oxygen bond in 5 was
CeCl3-mediated addition of acetylenic bis-lithium salts to aldehydes and ketones: An efficient route to bis-substituted alkyne diols
作者:Jefferson Luiz Princival、Jeiely Gomes Ferreira
DOI:10.1016/j.tetlet.2017.07.094
日期:2017.9
An efficient, chemoselective protocol to access propargylic diols via a CeCl3-mediated addition reaction is reported. Propargylic alcohols were transformed into the corresponding acetylenic bis-lithium salt intermediates, which react with aldehydes and ketones in the presence of dry CeCl3 to furnish the corresponding bis-substituted alkyne diols. This protocol does not involve protection-deprotection
Synthesis of alkyl allenyl sulfoxides from thiosuccinimides via [2,3]-sigmatropic rearrangement
作者:Adam B. Riddell、Michelle M. Michalski、Adrian L. Schwan
DOI:10.1080/10426507.2022.2157829
日期:——
synthesis of a broad range of alkyl allenyl sulfoxides via the [2,3]-sigmatropicrearrangement difficult, alternative sources of electrophilic sulfur were explored. Examination of various N-sulfanylimides revealed that thiosuccinimides are a viable sulfur source for the synthesis of alkyl allenyl sulfoxides via the [2,3]-sigmatropicrearrangement. With the optimized conditions of excess propargyl alcohol