β-(Phosphatoxy)alkyl and β-(acyloxy)alkyl radical migrations studied by laser flash photolysis

✍ Scribed by Seung-Yong Choi; David Crich; John H. Horner; Xianhai Huang; Martin Newcomb; Patrick O. Whitted

• Book ID: 104209067
• Publisher: Elsevier Science
• Year: 1999
• Tongue: French
• Weight: 700 KB
• Volume: 55
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(98)01143-0

✦ Synopsis

A number of ~(phosphatoxy)alkyl and ~(acyloxy)alkyl radicals have been ~nenu~ by laser flash photolysis of the corresponding Barton PTOC esters. Time resolved studies permitt~ the determination of rate constants and kinetic parameters for their rearrangement in benzene, THF, and acetonitrile. Migrations are accelerated by electron-donating groups on the alkyl moiety, electron-withdrawing groups on the migrating group, and more polar solvents. All reactions showed strictly first order kinetics. The results are interpreted in terms of concerted mechanisms occurring through three electron, three center and five electron, five center mechanisms.