(Tripltenyltin)cobaloxime as a Reagent for Radical Generation from Bromides

摘要

Intramolecular radical cyclization has increased in importance during the last decade and is widely used as a synthetic strategy. Radicals are often generated from halidc-a by the use of tributyltin hydride. This process, however, requires high dilution or slow addition of the tin hydride to avoid hydrogen transfer from the hydride to the organoradical, which results in the net reduction of the starting halide. The produced tributyltin halides are nonpolar and difficult to separate from the organic products in many cases although some efforts have been made to remove this disadvantage. In this paper, we describe a new method to produce the radical pair from (triphenyltinkobaloxime (1) (Figure 1) and bromides, which avoids these limitations.