Highly regioselective 7-endo-aryl radical cyclisation: synthesis of octahydro-2H-dibenzo[a,d]cycloheptenes
作者:Ajit K. Ghosh、Keya Ghosh、Sitaram Pal、Usha Ranjan Chatak
DOI:10.1039/c39930000809
日期:——
A highly efficient 7-endo-trig-aryl radical cyclisation of the alkene 6 and the vinylcyclohexanols 11a–d with tri-n-butyltin hydride leading to the respective octahydro-2H-dibenzo[a,d]cycloheptene derivatives 7 and 8 and 12a–d is reported.
4a-Substituted 1,1-dimethyl or 1-carbomethoxy-1-methyl hydrofluorenes carrying various substituents in the aromatic ring could be conveniently synthesized by Pd(0)-catalyzed Heck reaction. The required bromobenzyl-substituted ethylidene cyclohexane substrates were derived from Hagemann's ester (methyl analogue) via condensation with appropriate benzyl bromide, hydrolytic decarboxylation of the ester
Highly regioselective 8-endo-aryl radical cyclisation: a new synthetic route to decahydrodibenzo-[a,d]- and -[a,e]-cyclooctenols
作者:Keya Ghosh、Ajit K. Ghosh、Usha Ranjan Ghatak
DOI:10.1039/c39940000629
日期:——
A highly regioselective 8-endo-trig-aryl radical cyclisation of the vinylcyclohexanols 2a-c and allylcyclohexanols 6a-c with tri-n-butyltin hydride provides decahydrodibenzo-[a,e]- and -[a,d]-cyclooctenols 3a-c and 7a-c respectively, in moderate to good yields.
Regioselective Aryl Radical Cyclization. 1. Stereocontrolled Synthesis of Linearly Condensed Hydroaromatic Carbocyclic Systems through 6-endo-Ring Closures
作者:Sitaram Pal、Jayanta K. Mukhopadhyaya、Usha Ranjan Ghatak
DOI:10.1021/jo00089a009
日期:1994.5
The stereocontrolled synthesis of trans-octahydroanthracenes 3, 11a-c, and 14a-c and trans-octahydro-5aH-cyclohepta[b] naphthalene (27) through implementation of an efficient and highly regioselective 6-endo-trig-aryl radical cyclization of the respective 2-(o-bromoaryl)-1-methylenecyclohexanes 2, 10a-c, and 13a-c and 2-(o-bromobenzyl)-1-methylenecycloheptane (41) with tri-n- butyltin-hydride-is described. The radical cyclization of 2-(o-bromobenzyl)-1-methylenecyclopentane (43), in contrast, produced a mixture of the cis- and trans-hexahydro-1H-benz[f]indenes (38) and (37).
Regioselective 9- aryl radical cyclisation: A new synthetic route to decahydro-5-dibenzo[a,d] and [a,e]-cyclononenols