Transition-Metal-Catalyzed Allylic Substitution and Titanocene-Catalyzed Epoxypolyene Cyclization as a Powerful Tool for the Preparation of Terpenoids
作者:Andreas Gansäuer、José Justicia、Antonio Rosales、Dennis Worgull、Björn Rinker、Juan Manuel Cuerva、Juan Enrique Oltra
DOI:10.1002/ejoc.200600389
日期:2006.9
active substances are composed of sesquiterpene units linked to aromatic structures, especially substituted phenols. Here, we describe an efficient synthetic approach to this class of natural product from commercially available substances in a short sequence. The key transformations involve allylicsubstitution reactions using a palla
A Relay Strategy Actuates Pre-Existing Trisubstituted Olefins in Monoterpenoids for Cross-Metathesis with Trisubstituted Alkenes
作者:Karim A. Bahou、D. Christopher Braddock、Adam G. Meyer、G. Paul Savage、Zhensheng Shi、Tianyou He
DOI:10.1021/acs.joc.0c00067
日期:2020.4.3
benzylidene catalyzed olefincross-metathesis with homoprenyl benzenes. Successful implementation of this approach provided several epoxypolyenes as expected (E/Z, ca. 2-3:1). The method is further generalized for the cross-metathesis of pre-existing trisubstituted olefins in other relay-actuated Δ6,7-functionalized monoterpenoid alcohols with various other trisubstituted alkenes to form new trisubstituted
for hit compounds on promoting testosteronesynthesis and the methylpyrimidine ring-fused diterpenoid analog 7 was obtained as the hit. Based on the hit, a series of derivatives were designed, synthesized and evaluated for their effects on testosterone secretion in mouse Leydig TM3 cells. Most of the derivatives showed better activity in promoting testosteronesynthesis than the positive control compound
catalytic and highly stereoselective approach to precursors for epoxypolyene cyclizations based on copper-catalyzed allylic substitutions is described. The method allows introduction of various aromatic, benzyl, and alkyl groups without affecting epoxides. The compounds obtained are valuable starting materials for the synthesis of natural products and biologically active substances.
An arene-terminated epoxy olefin cyclization was promoted by a water-tolerant Lewis acid to give tri- and tetracyclic 3β-hydroxy terpenoids and steroid derivatives in 57 and 37% yields, respectively, per new formed ring up to 75%.