Formation of Benzo-Fused Carbocycles by Formal Radical Cyclization onto an Aromatic Ring
作者:Derrick L. J. Clive、Rajesh Sunasee
DOI:10.1021/ol070849l
日期:2007.7.1
An indirect method for effecting radical carbocyclization onto aromatic rings is described. Cross-conjugated dienones such as 13, readily prepared by Birch reduction of aromatic tert-butyl esters, in situ alkylation, and oxidation (10 --> 11 --> 12 --> 13), undergo radicalcyclization; the products (14) are aromatized by silylation, Saegusa oxidation, and treatment with BiCl3.H2O. A noteworthy feature
Formal radical closure onto aromatic rings—a general route to carbocycles
作者:Derrick L. J. Clive、Rajesh Sunasee、Zhenhua Chen
DOI:10.1039/b803308k
日期:——
A general method is described for indirectly effecting radical carbocyclization of an alkyl chain onto an aromatic ring. Birch reductive-alkylation of aromatic tert-butyl esters with α,Ï-dibromides, chromium(VI)-mediated oxidation of the resulting 1,4-dienes and Finkelstein displacement of Brâ with NaI gives cross-conjugated ketones that undergo radical cyclization. The products are easily aromatized to phenols by silylation, Saegusa oxidation and treatment with BiCl3.H2O. A special feature of the route is that it allows attachment of a substituent to the original aromatic ring in place of the phenolic oxygen of the normal product.