TANDEM RADICAL CYCLIZATIONS PROMOTED BY O-STANNYL KETYLS

This work summarizes an investigation of tandem radical cyclizations t riggered by O-stannyl ketyls. This organometallic reactive intermediat e is prepared from the reaction of tributyltin hydride (nBu(3)SnH) wit h a carbonyl functional group by a free radical chain mechanism. Sever al precursor substrates leading to ''separated,'' ''spiro,'' and ''fus ed'' cyclopentaniod ring systems were investigated which collectively have good synthetic potential for the construction of a wide array of substituted polycyclic products. (C) 1997 Elsevier Science Ltd.