Les groupes anioniques et nucleophiles sur la chainelaterale desylures de triphenylphosphonium provoquent un deplacement de lastereochimie de l'alcene obtenu vers l'isomere trans dans les 反应 avec des 醛。L'effet est souvent 加上重要的 avec des aldehydes aromatiques qu'avec des aldehydes aliphatiques。氧、羧酸、氨基和酰胺基的取代基研究
Stereochemistry of the Wittig reaction. Effect of nucleophilic groups in the phosphonium ylide
作者:Bruce E. Maryanoff、Allen B. Reitz、Barbara A. Duhl-Emswiler
DOI:10.1021/ja00287a040
日期:1985.1
Les groupes anioniques et nucleophiles sur la chaine laterale des ylures de triphenylphosphonium provoquent un deplacement de la stereochimie de l'alcene obtenu vers l'isomere trans dans les reactions avec des aldehydes. L'effet est souvent plus important avec des aldehydes aromatiques qu'avec des aldehydes aliphatiques. Les substituants etudies sont les groupes oxydo, carboxylate, amino et amido
Les groupes anioniques et nucleophiles sur la chainelaterale desylures de triphenylphosphonium provoquent un deplacement de lastereochimie de l'alcene obtenu vers l'isomere trans dans les 反应 avec des 醛。L'effet est souvent 加上重要的 avec des aldehydes aromatiques qu'avec des aldehydes aliphatiques。氧、羧酸、氨基和酰胺基的取代基研究
Stereochemical observations on the Wittig reaction of oxido phosphonium ylides with aldehydes
作者:Bruce E. Maryanoff、Allen B. Reitz、Barbara A. Duhl-Emswiler
DOI:10.1016/s0040-4039(00)81959-0
日期:1983.1
The reaction of aldehydes with oxido ylides shows a dramatic dependence of alkene stereochemistry on the distance between oxygen and phosphorus atomsl; ylides with proximal 0 and P atoms favor production of alkenes. The high stereoselectivity with γ-oxido ylides is not mainly attributable to intramolecular proton-exchange in a Wittig intermediate.
Constituents of Holothuroidea, 16. Determination of Absolute Configuration of the Branched Methyl Group in Ante-iso Type Side Chain Moiety on Long Chain Base of Glucocerebroside from the Sea Cucumber Holothuria leucospilota
branched methyl group in ante-iso type side chain moiety on the long chain base of glucocerebroside, HLC-2-A, which was isolated from the sea cucumber Holothuria leucospilota was determined. Oxidation of the glucocerebroside with ozone afforded C13-fragment including the ante-iso moiety. The optically active C13-fragment was synthesized asymmetrically by using the Wittig reaction from chiral synton for
Copper-Catalyzed Diastereoselective Synthesis of Trifluoromethylated Tetrahydrofurans
作者:Yanan Wang、Min Jiang、Jin-Tao Liu
DOI:10.1002/adsc.201501166
日期:2016.4.14
The copper‐catalyzed intramolecular diastereoselective trifluoromethylcycloetherification of homoallylic alcohols with Togni’s reagent as trifluoromethylating reagent was realized under mild conditions. Various trifluoromethylated tetrahydrofurans were synthesized in moderate to good yields. Moreover, a wide range of common functional groups was tolerated.
Catalytic Asymmetric Vinylogous Prins Cyclization: A Highly Diastereo- and Enantioselective Entry to Tetrahydrofurans
作者:Youwei Xie、Gui-Juan Cheng、Sunggi Lee、Philip S. J. Kaib、Walter Thiel、Benjamin List
DOI:10.1021/jacs.6b09129
日期:2016.11.9
cyclization. This reaction constitutes an efficient approach for highly diastereo- and enantioselective synthesis of tetrahydrofurans (THFs) and is catalyzed by a confined chiral imidodiphosphoric acid (IDP). Aromatic and heteroaromatic aldehydes react with various 3,5-dien-1-ols to afford 2,3-disubstituted THFs in excellent selectivity (d.r. > 20:1, e.r. up to 99:1). Aliphatic aldehydes react with similarly