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
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).