合成这些 de [dimethyl-5,5 dioxannylidene-2]-3 cyclopentanecarboxylate demethyle a partir dedimethyl-6,6 methylene-1 dioxa-4,8 spiro [2.5] 辛烷和 de crotonate demethyle。Le crotonate demethyle peut etre 替换 par d'autres 酯(例如庚烯-2oate demethyle)或内酯(例如二氢呋喃酮-2)。在 obtient dans ce dernier cas des 上推导 de cyclopenta [c] furannone
Wittig Reactions in Water Media Employing Stabilized Ylides with Aldehydes. Synthesis of α,β-Unsaturated Esters from Mixing Aldehydes, α-Bromoesters, and Ph<sub>3</sub>P in Aqueous NaHCO<sub>3</sub>
作者:Amer El-Batta、Changchun Jiang、Wen Zhao、Robert Anness、Andrew L. Cooksy、Mikael Bergdahl
DOI:10.1021/jo070665k
日期:2007.7.1
range of stabilized ylides and aldehydes. Despite sometimes poor solubility of the reactants, good chemical yields normally ranging from 80 to 98% and high E-selectivities (up to 99%) are achieved, and the rate of the reactions in water is unexpectedly accelerated. The efficiency of water as a medium in the Wittig reaction is compared to conventional organic solvents ranging from carbon tetrachloride
Nucleophilic attack of 2-sulfinyl acrylates: A mild and general approach to sulfenic acid anions
作者:Suneel P. Singh、Jennifer S. O'Donnell、Adrian L. Schwan
DOI:10.1039/b917217c
日期:——
An increasing number of reactions of sulfenic acidanions are being demonstrated in the literature. As such, mild, general and reliable means for the generation of sulfenates are due. In the current paper, an addition/elimination of 2-sulfinyl acrylates using various nucleophiles is demonstrated and evaluated as a protocol for alkane- and arenesulfenate generation. Cyclohexanethiolate, methoxide and
Stereoselective synthesis of α,β-unsaturated esters
作者:Marc Larchevêque、Alain Debal
DOI:10.1039/c39810000877
日期:——
Reaction of α-silylated ester magnesium enolates with aldehydes affords exclusively one diastereoisomer of the two possible β-hydroxy silanes which give pure E-unsaturated esters on acid work-up.
Reactions of α,β-unsaturated esters with aldehydes were catalyzed by 0.2 equiv of lithium benzenethiolate in the presence of phenyl trimethylsilyl sulfide to afford the conjugate addition-aldol tandem reaction products in the anti stereoselectivity and good to high yields.
A CONVENIENT STEREOSPECIFIC SYNTHESIS OF α,β-UNSATURATED CARBOXYLIC ESTERS VIA THE PALLADIUM-CATALYZED CARBONYLATION OF 1-ALKENYLBORANES
作者:Norio Miyaura、Akira Suzuki
DOI:10.1246/cl.1981.879
日期:1981.7.5
1-Alkenyiboranes readily prepared by the hydroboration of alkynes react smoothly with carbon monoxide in the presence of palladium chloride and sodium acetate in methanol to give the corresponding α,β-unsaturated carboxylic esters with retention of configuration with respect to alkenylboranes in good yields.