Intramolecular radical additions to the azo group. Fast and indiscriminate 5-exo and 6-endo cyclizations

ALJ Beckwith, S Wang, J Warkentin

Index: Beckwith, Athelstan L. J.; Wang, Shaofang; Warkentin, John Journal of the American Chemical Society, 1987 , vol. 109, # 17 p. 5289 - 5291

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Citation Number: 39

Abstract

Ratios of rate constants, k5/kH and k6/kH (Table I) from closure of 3 to 4 (5-exo closure) and 5 (6-endo closure) were calculated from the product composition and the concentration of 2. Substitution into average values of k5/kH and k6/kH, of the literature5 value of kH for attack of the phenyl radical on 2, kLh (82" C)= 9.0 X lo8 M-'s-', gives k3'= 1.5 X lo9 SI, k%= 2.3 X lo9 sl, k: b= 4.5 X lo8 s-', and k $= 9.7 X los SI. Although the validity of the above value of kLh ...