Pyrrolizidinone and indolizidinone synthesis: generation and intramolecular addition of .alpha.-acylamino radicals to olefins and allenes
作者:Duane A. Burnett、Joong Kwon Choi、David J. Hart、Yeun Min Tsai
DOI:10.1021/ja00338a033
日期:1984.12
Des radicaux α-acylamino peuvent etre generes par traitement de derives de phenylthio-2-, phenylseleno-2 ou methylthio-2 butene-3'yl-1 pyrrolidones-2 par l'hydrure de tributyl-Sn en presence de AIBN. Ces radicaux subissent des reactions intramoleculaires pour donner des indolizidinones et des pyrrolizidinones
Des radicaux α-acylamino peuvent etregeneres par traitement de 衍生 de phenylthio-2-, phenylseleno-2 oumethylthio-2 butene-3'yl-1 pyrrolidones-2 par l'hydrure de tributyl-Sn en Ces radicaux subissent des反应分子内反应donner des indolizidinones et des pyrrolizidinones
Free radical cyclizations in alkaloid synthesis: (+)-heliotridine and (+)-hastanecine
作者:Joong-Kwon Choi、David J. Hart
DOI:10.1016/s0040-4020(01)97176-5
日期:1985.1
hydride and AIBN affords mixtures of reduction and cyclization products. Cyclization products partition between indolizidinones and pyrrolizidinones depending on the terminal alkyne substituent. When the terminal substituent is a trimethylsilyl group, synthetically useful yields of pyrrolizidinones are obtained. Applications of this chemistry to the synthesis of (+)-heliotridine (2) and (+)-hastanecine (3)
Substituent effects on 2-aza-5-hexynyl radical cyclization regiochemistry
作者:Joong-Kwon Choi、David J. Hart、Yeun-Min Tsai
DOI:10.1016/s0040-4039(00)85708-1
日期:1982.1
Cyclizations of several N-acyl-2-aza-5-hexynyl radicals are described. The regiochemical course of these cyclizations depend on the nature of substituents at the alkyne terminus.
New methods for alkaloid synthesis: .alpha.-acylamino radical cyclizations
作者:David J. Hart、Yeun-Min Tsai
DOI:10.1021/ja00369a050
日期:1982.3
Titanium-Mediated Cyclization of ω-Vinyl Imides in Alkaloid Synthesis: Isoretronecanol, Trachelanthamidine, 5-Epitashiromine, and Tashiromine
作者:Se-Ho Kim、Seok-In Kim、Sheng Lai、Jin Kun Cha
DOI:10.1021/jo9907383
日期:1999.9.1
A newmethod for the stereocontrolled synthesis of pyrrolizidine and indolizidine alkaloids by means of titanium-mediated cyclization of omega-vinyl imides is described. The general procedure involves treatment of readily available omega-vinyl imides 9 and 10 with 2.5 equiv of cyclopentylmagnesium chloride in the presence of ClTi(O-i-Pr)(3) (1.1 equiv) and subsequent stereoselective reduction of the