Kumulierte Ylide XIX.1Acylphosphoniumylide durch kettenverlängernde Difunktionalisierung von Grignard-Verbindungen mit Ketenylidentriphenylphosphoran. Anwendung zur Synthese (E)-α,β-ungesättigter-Ketone und der Königinsubstanz
Synthesis of trifluoromethyl-/cyclopropyl-substituted 2-isoxazolines by DBU-promoted domino reaction
作者:Xiao-Dong Liu、Hai-Yan Ma、Chun-Hui Xing、Long Lu
DOI:10.1016/j.cclet.2017.03.031
日期:2017.8
cyclopropyl substituted 2-isoxazolines were synthesized via a DBU-promoted domino reaction of β-trifluoromethyl-/β-cyclopropyl-substituted enones with hydroxylamine. The domino reaction consists of a Michael addition and the followed cyclization. A wide range of 3-substituted 5-cyclopropyl-5- trifluoromethyl-2-isoxazolines were obtained in good to excellent yields under mild reaction conditions. The method
High-Pressure Accelerated Asymmetric Organocatalytic Friedel–Crafts Alkylation of Indoles with Enones: Application to Quaternary Stereogenic Centers Construction
organocatalytic Friedel–Craftsalkylation of indoles with α,β-unsaturated ketones was found to be efficiently accelerated under high-pressure conditions with a low loading of chiral primary amine salts with good yield and enantioselectivity up to 90%. This approach also allows, for the first time, selected indole derivatives containing quaternary stereogenic centers to be obtained from prochiral β,β-disubstituted
A general and efficient synthesis of allenes using a palladium(0)/diethylzinc system is described. Treatment of mesylates or trichloroacetates of (E)- or (Z)-2-bromoalk-2-en-1-ols with diethylzinc in the presence of a catalytic amount of palladium(0) affords allenes bearing an aminoalkyl, alkyl, or aryl substituent(s) in good to high yields. No transfer of chirality from the stereogenic center carrying
Diastereoselective synthesis of epoxide-fused benzoquinolizidine derivatives using intramolecular domino aza-Michael addition/Darzens reaction
作者:Jiajia Guo、Xiaoyang Sun、Shouyun Yu
DOI:10.1039/c3ob42068j
日期:——
An efficient and diastereoselective strategy based on an intramolecular dominoaza-Michael/Darzens reaction to synthesize epoxide-fused benzoquinolizidines has been described. Three bonds (1 C–C, 1 C–N and 1 C–O), three rings and three chiral centers can be constructed in a single pot under very mild conditions. All the products were isolated in only one diastereomer with 40–80% yields.