The study of intramolecular free radical cyclizations of α-sulfonyl and α-sulfinyl radicals
作者:Tsai Yeun-Min、Ke Bor-Wen、Lin Chao-Hsiung
DOI:10.1016/s0040-4039(00)98025-0
日期:1990.1
α-Sulfonyl and α-sulfinyl radicals can be generated from the corresponding α-halosulfones and αhalosulfoxides. Our results indicate that these radicalscyclize very efficiently.
作者:Sureshbabu Dadiboyena、Jianping Xu、Ashton T. Hamme
DOI:10.1016/j.tetlet.2006.12.005
日期:2007.2
The regioselectivesynthesis of 3,5-disubstitutedisoxazoles was achieved through the 1,3-dipolar cycloaddition of nitrile oxides with 1,1-disubstituted bromoalkenes. The substituted bromoalkenes function as alkyne synthons which were used to construct 5,5-disubstituted bromoisoxazoline intermediates that aromatize to the analogous isoxazoles through the loss of HBr.
Generation and intramolecular cyclization of α-sulfinyl and α-sulfonyl radicals
作者:Bor-Wen Ke、Chao-Hsiung Lin、Yeun-Min Tsai
DOI:10.1016/s0040-4020(97)00472-9
日期:1997.6
alpha-Phenylsulfinyl and alpha-Phenylsulfonyl radicals are generated by the reactions of alpha-chlorosulfoxides and alpha-chlorosulfones with tributyltin hydride, respectively. High reaction concentration (0.2 M) is required to ensure efficient generations of these radicals. The 5-exo-type intramolecular cyclizations of these radicals are studied. The cyclization is most successful when the olefin is terminally substituted with an ester group. The sulfinyl group only induces mild diastereoselectivity on the cyclization. (C) 1997 Elsevier Science Ltd.