Generation and intramolecular cyclization of α-sulfinyl and α-sulfonyl radicals
摘要:
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.
photocatalyzed oxidation of cis-2-methylcyclopentyl phenyl sulfoxide in the presence of Ag2SO4 in MeCN/H2O leads to the formation of 1-methylcyclopentanol, 1-methylcyclopentyl acetamide, and phenyl benzenethiosulfonate as the main reaction products. It is suggested that the C−S heterolysis in the radical cation is an unimolecular process leading to an ionradical pair. Fast 1,2-hydride shift in the secondary
在MeCN / H 2 O中存在Ag 2 SO 4的情况下,TiO 2光催化氧化顺式-2-甲基环戊基苯基亚砜导致形成1-甲基环戊醇,1-甲基环戊基乙酰胺和苯基苯硫磺酸酯作为主要反应产物。建议在自由基阳离子中的CS杂解是导致离子自由基对的单分子过程。次级碳正离子中1,2-氢化物的快速移位导致1-甲基环戊基碳正离子通过与H 2 O和MeCN反应形成观察到的产物。还可能发生H 2 O对离子自由基对的攻击,但作为次要途径(<3%),会形成反式-2-甲基环戊醇。