Control of dispersity and stereochemistry in free radical telomerizations: A radical addition, cyclization, chain transfer (ACT) strategy

Article abstract of DOI:10.1021/ja00101a049

A general strategy for the stereoselective preparation of n = 2 telomers displaying narrow dispersity is reported. Covalent assemblies composed of a rigid base compound, flexible tethers, and oxazolidine acrylamide monomers were reacted under free radical conditions to afford macrocyclic precursors to the targeted telomers through an addition, cyclization, chain transfer (ACT) sequence. Subsequent hydrolysis and esterification afforded the desired products with excellent stereoselectivity and teloselectivity. Systematic variation of system components (the rigid base compound, the functionality linking base compound to the tethers, the length of the tethers, the configuration at the site of oxazolidine attachment, and the auxiliary blocking group) allowed for identification of the structural elements necessary for successful implementation. It was found that each of these variables had a marked influence on the performance of the covalent assembly.