Cascade radical cyclisations leading to steroid ring constructions. Regio- and stereo-chemical studies using ester- and fluoro-alkene substituted polyene acyl radical intermediates
作者:Haydn M. Boehm、Sandeep Handa、Gerald Pattenden、Lee Roberts、Alexander J. Blake、Wan-Sheung Li
DOI:10.1039/b002999h
日期:——
the E-substituted diene selenyl ester 7 underwent sequential cyclisations in the presence of Bu3SnH-AIBN leading to the trans-decalone 8 exclusively, the corresponding Z- and E-isomers of the methoxycarbonyl-substituted diene 16, under similar conditions, gave rise to a 2∶1 mixture of the trans- and cis-decalones 17a and 17b respectively in 62–73% yield. Cyclisation of the triene selenoate 30 led to
Cascade radical processes leading to polycycle constructions. The total synthesis of spongian-16-one
作者:Gerald Pattenden、Lee Roberts
DOI:10.1016/0040-4039(96)00740-x
日期:1996.6
A concise total synthesis of the marine sponge metabolite spongian-16-one 1, which features a novel cascade of three consecutive 6-endo-trig radical cyclisations from a polyene acyl radical intermediate as a key step, viz9 → 10, is described.
Cascade radical cyclisations leading to polycyclic diterpenes. Total synthesis of (±)-spongian-16-one
作者:Gerald Pattenden、Lee Roberts、Alexander J. Blake
DOI:10.1039/a708042e
日期:——
A cascade of three consecutive 6-endo-trig radical cyclisations from the polyene acyl radical intermediate 12 derived from the selenoate 11 is used to construct the trans,anti,trans,anti,cis-tetracyclic keto lactone 20 in one step. Manipulation of the ketone function in 20 to the corresponding gem-dimethyl substituted carbon then completed a concise synthesis of the marine metabolite spongian-16-one 1.
The hydrindanol (2), a C/D-ringsynthon of vitaminD3metabolites, has been synthesized enantioselectively by the use of stereoselective epoxy alcohol-initiated polyalkene cyclisation as a key step.