Acceleration of the 4-exo radical cyclization to a synthetically useful rate. Cyclization of the 2,2-dimethyl-5-cyano-4-pentenyl radical

Article abstract of DOI:10.1016/S0040-4039(00)89002-4

The title radical, formed in the reaction of the corresponding bromide with Bu₃SnH, cyclizes in a 4-exo fashion to give the (3,3-dimethylcyclobutyl)cyanomethyl radical. At 50°C, the rate constant for cyclization is 1.9 x 10⁴s^-1.