29835-16-3Relevant academic research and scientific papers
Phenyl versus alkyl migration in the fragmentation of alkoxychlorocarbenes
Moss, Robert A.,Fu, Xiaolin
, p. 235 - 237 (2007/10/03)
Phenyl versus methyl (alkyl) group migration is assessed in the fragmentations of neophyloxychlorocarbene, 2,2-diphenylpropyloxychlorocarbene, and 1-phenylcyclopropylmethoxychlorocarbene. Rate constants and activation parameters of the fragmentations are also reported.
Isotope effect and kinetic studies of the reaction of tertiary alcohols with triphenylphosphine-carbon tetrachloride: Ion pair or concerted?
Dabbagh, Abduol Hossein,Faghihi, Khalil
, p. 3611 - 3617 (2007/10/03)
Kinetics of the reactions of 1,2,3-triphenyl-2-propanol (1), 1,2- diphenyl-2-propanol (2) and 3,3,3-trideuterio-1,2-diphenyl-2-propanol (3) with triphenylphosphine-carbon tetrachloride in the temperature range of 25- 78°C in several solvents are investigated. In a non-polar solvent (CCl4), the reaction of (2) proceeds via intermolecular anti E2 elimination and/or intermolecular SN2 nucleophilic substitution (28% substitution, ratio of 2- alkene/l-alkene=l.06, E/Z>49). In a polar solvent (CH3CN) reaction proceeds via El and/or S(N)1 (24% substitution, 2-alkene/1-alkene=1.9, E/Z≥6. At equilibrium, the ratio of 2-alkene/1-alkene is equal to 99 with E/Z≥4.21. The primary kinetic isotope effect (k(H)/k(D)) for the elimination pathway in the non-polar solvent is equal to 4.90 and 3.90 at temperatures of 25 and 60δC, respectively. A small secondary β-isotope effect of 1.10 was observed for substitution reaction at both temperatures. Direction of substitution (S(N)2 vs. E2) depends on temperature and polarity of the solvent. The energetics (δS(+), δG(+), δH(+)), the rate orders, and optimization of molecular geometry of intermediates by semiempirical methods (AM1 and CNDO) all agree with intermolecular E2 and S(N)2 mechanisms. New rules for stereoselectivity and Hofmann-Saytzeff eliminations are considered. 2000 Elsevier Science Ltd.
