RATE CONSTANTS FOR 5-EXO AND 6-EXO SECONDARY ALKYL RADICAL CYCLIZATIONS ONTO N,N-DIPHENYLHYDRAZONES

Authors
STURINO CF FALLIS AG
Citation
Cf. Sturino et Ag. Fallis, RATE CONSTANTS FOR 5-EXO AND 6-EXO SECONDARY ALKYL RADICAL CYCLIZATIONS ONTO N,N-DIPHENYLHYDRAZONES, Journal of organic chemistry, 59(22), 1994, pp. 6514-6516
Citations number
25
Categorie Soggetti
Chemistry Inorganic & Nuclear
Journal title
Journal of organic chemistry → ACNP
ISSN journal
00223263
Volume
59
Issue
22
Year of publication
1994
Pages
6514 - 6516
Database
ISI
SICI code
0022-3263(1994)59:22<6514:RCF5A6>2.0.ZU;2-D
Abstract
Competitive ''radical clock''-type cyclizations of hydrazones and alke nes established that the rate constants for 5-exo cyclizations onto N, N-diphenylhydrazones are 1.1 x 10(8) s(-1) and 4.6 x 10(7) s(-1) at 80 degrees C to the cis- and trans-cyclopentylhydrazines, respectively ( about 200 times faster than the corresponding cyclization rate for 5-e xo alkenes). The 6-exo hydrazone rate constant is 9.4 x 10(5) s(-1) at 80 degrees C for both cis and trans isomers with activation barriers of 5.6 and 6.2 kcal/mol, respectively.