Radical cyclizations represent powerful synthetic strategies for the assembling of heterocycles. Most radical cyclizations are based on the addition to C C double or triple bonds. On the contrary, the addition to C O double bonds is rarely reported, since it proceeds reversibly due to the formation of thermodynamically unfavorable alkoxy radicals. Herein we report our attempts to construct substituted pyrrolidin-3-ols by tin-mediated radical cyclization of 5-phenylseleno-3-aza-pentanals. These rings are widely represented in natural products and drug candidates with various biological activities.
Carbamoylmethyl Radical Cyclizations and Applications to the Synthesis of Natural Products.