RESUMO
A mild, diastereoselective synthesis of fused lactone-pyrrolidinones using an oxidative radical cyclization is reported. The methodology is demonstrated in a formal synthesis of (-)-salinosporamide A.
Assuntos
Lactonas/síntese química , Pirróis/síntese química , Pirrolidinonas/síntese química , Ciclização , Lactonas/química , Estrutura Molecular , Oxirredução , Pirróis/química , Pirrolidinonas/química , EstereoisomerismoRESUMO
We describe a palladium-catalyzed diastereo- and enantioselective formal [3 + 2]-cycloaddition between substituted vinylcyclopropanes and electron-deficient olefins in the form of azlactone- and Meldrum's acid alkylidenes to give highly substituted cyclopentane products. By modulation of the electronic properties of the vinylcyclopropane and the electron-deficient olefin, high levels of stereoselectivity were obtained. The remote stereoinduction afforded by the catalyst, distal from the chiral pocket generated by the ligand, is proposed to be the result of a new mechanism invoking the Curtin-Hammett principle.
