Quantitating the effect of an ortho substituent on cyclization and intramolecular hydrogen-transfer reactions of aryl radicals.
Reduction of allyl 2-iodobenzyl malonates with triphenyltin hydrides generates aryl radicals that partition between 6-exo cyclization, 7-endo cyclization, and 1,5-hydrogen atom transfer. Rate constants for all of these processes are high (>10(8) M(-)(1) s(-)(1)), and the rates are only marginally reduced (<33%) by the introduction of methyl group ortho to the reacting radical.
Curran
Dennis P
DP
Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA. curran@pitt.edu
Fairweather
Neil
N
D000478:Alkylation; D002384:Catalysis; D003500:Cyclization; D006844:Hydrocarbons, Cyclic / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D007202:Indicators and Reagents; D007700:Kinetics; D008314:Malonates / Q000737:chemistry*; D008745:Methylation; D015394:Molecular Structure
D006844:Hydrocarbons, Cyclic; D007202:Indicators and Reagents; D008314:Malonates; D006859:Hydrogen