Addition of zinc homoenolates to acetylenic esters and amides: a formal [3 + 2] cycloaddition
作者:Michael T. Crimmins、Philippe G. Nantermet、B. Wesley Trotter、Isabelle M. Vallin、Paul S. Watson、Lynne A. McKerlie、Tracy L. Reinhold、Adrian Wai Hing Cheung、Katherine A. Stetson
DOI:10.1021/jo00057a013
日期:1993.2
The copper-catalyzed conjugate addition-cycloacylation reaction of zinc homoenolates with acetylenic esters or acetylenic amides is described. The zinc homoenolate is prepared from [(ethoxycyclopropyl)oxy]trimethylsilane and zinc chloride in ether. Addition of an acetylenic amide or ester provides 2-carboxamido-or 2-carboalkoxy-3-alkylcyclopent-2-en-1-ones in good to excellent yields. The reaction can be carried out in the presence of a variety of sensitive functional groups including epoxides, alpha,beta-unsaturated esters, acetals, silyl ethers, and furans.
Addition of zinc homoenolates to acetylenic esters: a formal [3+2] cycloaddition
作者:Michael T. Crimmins、Philippe G. Nantermet
DOI:10.1021/jo00301a003
日期:1990.7
CRIMMINS, MICHAEL T.;NANTERMET, PHILIPPE G., J. ORG. CHEM., 55,(1990) N4, C. 4235-4237
作者:CRIMMINS, MICHAEL T.、NANTERMET, PHILIPPE G.
DOI:——
日期:——
Synthetic studies on the ginkgolides: total synthesis of (.+-.)-bilobalide
作者:Michael T. Crimmins、David K. Jung、Jeffrey L. Gray
DOI:10.1021/ja00061a014
日期:1993.4
Two syntheses of the C15 ginkgolide, bilobalide, are presented. One approach results in a formal synthesis by intersecting an intermediate in the Corey synthesis, while a second approach results in a completed totalsynthesis which is considerably shorter than the first. Both approaches rely on a stereoselective intramolecular [2+2] photocycloaddition to control much of the stereochemistry. A diastereoselective