October 4, 2002

Anodic Olefin Coupling Reactions Involving Ketene Dithioacetals: Evidence for a ‘Radical-type’ Cyclization

Yongmao Sun and Kevin D. Moeller
Tetrahedron Letters, 2002, 43(40), 7159-7161

A series of anodic coupling reactions between ketene dithioacetal groups and enol ethers have been studied in order to probe why some of the cyclizations are successful while other closely related attempts fail. It has been found that the success of the cyclization reactions strongly depends on the location of substituents on the olefins. The reactions are highly sensitive to substituents on the terminating olefin but not to substituents on the initial radical cation. This behavior is consistent with what has been observed previously with radical cyclization reactions.

The success of anodic couplings between ketene dithioacetals and enol ethers that form quaternary centers show the same dependence on substituent location that is observed for radical cyclization reactions.