Intramolecular [4 + 1] pyrroline annulation via azide-diene cycloadditions. 2. Formal stereoselective total syntheses of (.+-.)-platynecine, (.+-.)-hastanecine, (.+-.)-turneforcidine, and (.+-.)-dihydroxyheliotridane
Yeast-mediated resolution of .beta.-keto esters of prochiral alcohols
作者:Tomas Hudlicky、Toshiya Tsunoda、Kumar G. Gadamasetti、Jerry A. Murry、Gary E. Keck
DOI:10.1021/jo00011a031
日期:1991.5
Several racemic alcohols were converted to their beta-keto esters with diketene, and the resulting compounds were subjected to kinetic resolution by means of bakers' yeast. The unreacted keto esters were separated from the reduced hydroxy esters by chromatography, and the products were analyzed for levels of enantiomeric excess. Chiral shift reagents, Mosher esters, and optical rotation of the enantiomers of the alcohols were the criteria used to determine the optical integrity of the resolved alcohols after hydrolysis of the esters. Absolute stereochemistry was determined for the resolution products of all the substrates. Some rationale is advanced to account for the observed levels of enantiomeric excess and for the apparent diastereospecificity of the enzymatic resolution. The utility of this process as means of resolution of prochiral alcohols as well as an application of such resolution to the preparation of both enantiomers of a pyrrolizidine alkaloid synthon are indicated.
A new indolizidine synthesis
作者:Saïd Boulaajaj、Thierryp Le Gall、Michel Vaultier、René Grée、Loïc Toupet、Robert Carrié
DOI:10.1016/s0040-4039(00)95414-5
日期:1987.1
HUDLICKY, TOMAS;TSUNODA, TOSHIYA;GADAMASETTI, KUMAR G.;MURRY, JERRY A.;KE+, J. ORG. CHEM., 56,(1991) N1, C. 3619-3623
作者:HUDLICKY, TOMAS、TSUNODA, TOSHIYA、GADAMASETTI, KUMAR G.、MURRY, JERRY A.、KE+
DOI:——
日期:——
HUDLICKY, TOMAS;SEOANE, GUSTAVO;LOVELACE, THOMAS C., J. ORG. CHEM., 53,(1988) N 9, 2094-2099
作者:HUDLICKY, TOMAS、SEOANE, GUSTAVO、LOVELACE, THOMAS C.
DOI:——
日期:——
Intramolecular [4 + 1] pyrroline annulation via azide-diene cycloadditions. 2. Formal stereoselective total syntheses of (.+-.)-platynecine, (.+-.)-hastanecine, (.+-.)-turneforcidine, and (.+-.)-dihydroxyheliotridane
作者:Tomas Hudlicky、Gustavo Seoane、Thomas C. Lovelace