Radical and Palladium-Catalyzed Cyclizations to Cyclobutenes: An Entry to the BCD Ring System of Penitrem D
作者:Alexey Rivkin、Felix González-López de Turiso、Tadamichi Nagashima、Dennis P. Curran
DOI:10.1021/jo049873s
日期:2004.5.1
A novel approach toward the synthesis of the BCD ring system of penitrem D is described. The strategy capitalizes on the fast cyclization rates of aryl radicals into cyclobutenes and allows access to a variety of fused tricyclic structures. Radical/polar crossover reactions of precursors 24−29 promoted by samarium diiodide in the presence of HMPA and acetone allow access to the fully functionalized