title: Studies toward the total syntheses of cucurbitacins B and D.
abstract: Synthetic efforts toward the convergent construction of the tetracyclic triterpenoids cucurbitacins B and D are described. The results of a Diels-Alder study examining the effects of steric and electronic variations of 2-methyl-2-cyclohexenone on the endo/exo-diastereoselectivity of the reaction are presented. The diastereomer of the core of the cucurbitacins, epimeric at C8, C9, and C10, 51, was synthesized via a highly regio- and stereoselective Diels-Alder reaction of the diene 4 and the novel dienophile 50.
authors.affiliation: Department of Chemistry, Biochemistry, University of California, Los Angeles, California 90095-1569, USA. jung@chem.ucla.edu
authors.forename: Michael E
authors.initials: ME
authors.lastname: Jung
authors.forename: Rebecca M
authors.initials: RM
authors.lastname: Lui
mesh_terms: D013237:Stereoisomerism; D013379:Substrate Specificity; D014315:Triterpenes / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D014315:Triterpenes; C041246:cucurbitacin B; C038105:cucurbitacin D