herein shows that sulfonate/halide exchange can be advantageously performed in THF to avoid several side reactions such as elimination and epimerization when the reaction is performed from a chiral alkyl sulfonate or a substrate having a CH acidic chiral center. The main limitation of this procedure was found to be the conversion of secondaryalkyl sulfonates to alkyl chlorides. In this case, the
Cross-interaction constants as a measure of the transition-state structure. 14. Nucleophilic substitution reactions of 1-phenyl-2-propyl benzenesulfonates with anilines in methanol
作者:Ikchoon Lee、Won Heui Lee、Hai Whang Lee
DOI:10.1021/jo00015a022
日期:1991.7
The kinetics of the reactions between 1-phenyl-2-propyl benzenesulfonates (PPB) and anilines in methanol at 65.0-degrees-C are investigated, and the mechanism is discussed on the basis of various selectivity parameters, especially on the cross-interaction constants, rho-ij. The aryl participation is significant only with the p-CH3O-substituted substrate. rho-XZ is positive, and accordingly the transition state (TS) variations with substituents are consistent with those predicted by the potential energy surface diagram. The TS is of an intermediate type between that for an associated (tight) and a dissociated (loose) S(N)2 process; it is rather tight, but bond breaking is ahead of bond making with positive charge development at the reaction center in the TS. The possibility of front-side attack with a four-center TS is precluded because of strong steric hinderance in a close approach of the two bulky groups, the nucleophile and leaving group, on the same side in the front-side attack.
Lee, Ikchoon; Lee, Won Heui; Lee, Hai Whang, Journal of the Chemical Society. Perkin transactions II, 1991, # 5, p. 785 - 791
作者:Lee, Ikchoon、Lee, Won Heui、Lee, Hai Whang、Lee, Byung Choon
DOI:——
日期:——
The direct anti-Markovnikov addition of mineral acids to styrenes
作者:Dale J. Wilger、Jean-Marc M. Grandjean、Taylor R. Lammert、David A. Nicewicz
DOI:10.1038/nchem.2000
日期:2014.8
hydrogen atom donor. The nucleophile counterion plays a critical role by ensuring high reactivity, with 2,6-lutidinium salts typically furnishing the best results. The nature of the redox-activehydrogen atom donor is also consequential, with 4-methoxythiophenol providing the best reactivity when 2,6-lutidinium salts are used. A novel acridinium sensitizer provides enhanced reactivity within several of
Abstract Secondary alkyl chlorides have been efficiently prepared from secondary alkyl sulfonates under mild and user-friendly conditions. The exchange reaction was generally performed by using benzyltributylammonium chloride in acetone (reflux, 30 min). Yields are excellent from functionalized, base-sensitive and hindered secondary alkyl sulfonates. Secondary alkyl chlorides have been efficiently