Mechanism of Abietadiene Synthase Catalysis: Stereochemistry and Stabilization of the Cryptic Pimarenyl Carbocation Intermediates
作者:Matthew M. Ravn、Reuben J. Peters、Robert M. Coates、Rodney Croteau
DOI:10.1021/ja017734b
日期:2002.6.1
carbocation/OPP anion stabilization of the secondary sandaracopimaren-15-yl(+) ion. The failure of 8 beta-hydroxy-17-nor CPP (19b) to undergo enzymaticcyclization was taken as evidence that 9 is bound with a "coplanar" side chain conformation and that the S(N)' cyclization occurs on the 17 alpha face. The routing of the sandarcopimara-15-en-8-yl carbocation toward various diterpenes in biogenetic schemes
Experiments directed toward the total synthesis of terpenes. XI. The total synthesis of (.+-.)-rimuene and (.+-.)-13-epi-rimuene
作者:Robert E. Ireland、Lewis N. Mander
DOI:10.1021/jo01278a041
日期:1967.3
Acid-catalysed decomposition of β,γ-unsaturated diazo-ketones preparation of 4,4-dimethyl-<scp>D</scp>-nor-steroidal systems from pimaradiene and sandaracopimaradiene precursors
4-Dimethyl-17-nor-5α,13α-androst-8-en-16-one (9) and 3β-acetoxy-4,4-dimethyl-17-nor-5α-androst-8-en-16-one (19) have been prepared by the acid-catalysed intramolecular cyclization of 16-diazopimar-8(14)-en-15-one (7) and 3β-acetoxy-16-diazoisopimar-7-en-15-one (16) prepared from pimara-8(14),15-diene (5) and isopimara-7,15-dien-3β-ol acetate (10), respectively.