Two Types of Intramolecular Homolytic Substitution Reactions at Group XIV Atoms

摘要

4-[(Trimethylstannyl)diphenylsilyl]butanoyl radical,arising from the corresponding 3-(stannylsilyl)propyl radical and CO,undergoes an S_Hi reaction at Si with extrusion of trimethyltin radical to give silacyclopentanone.The parent 3-(stannylsilyl)propyl radical was also found to isomerize to(3-stannylpropyl)silyl radical via a 1,4-Sn shift from Si to C with a rate constant of 9.3 x 10~4 s~(-1)at 80 deg C.Ab initio and DFT MO calculations support a front-side attack mechanism.