Neighboring Group Participation in the Oxidation of Hydroxy Sulfides. Control of the Reaction Courses and Products
作者:Yoshio Ueno、Tadaaki Miyano、Makoto Okawara
DOI:10.1246/bcsj.53.3615
日期:1980.12
sulfides [PhS(CH2)nCH(OH)R] with hexabutyldistannoxane (HBD)–bromine system was studied in order to clarify neighboringgroupparticipation during the course of reaction. The oxidation products were found to be highly dependent on the positions of the two functional groups [sulfide and hydroxyl group]. Thus hydroxy sulfoxides [PhSO(CH2)nCH(OH)R] were obtained as the main product when n=1 or 2, bromo sulfones
The enantiomeric cyclic, five-membered vic-diolsreacted with (PhS)2/Bu3P in benzeneat 80 °C giving the corresponding bis(phenylsulfanyl) derivatives(42-74%) with complete inversion of configurationat both stereogenic centers. Similar reaction conditions were alsosuccessfully used for the enantiospecific transformation of a singlehydroxy group into the respective enantiomeric thioether function.For other vic-diols the neighboring groupparticipation hampered the stereoselectivity of the double substitution.
对映体环状五元沧二醇与 (PhS)2/Bu3P 在苯中于 80 °C 发生反应,生成相应的双(苯硫基)衍生物(42-74%),两个立体中心的构型完全反转。类似的反应条件也成功地用于将单羟基对映体转化为相应对映体的硫醚官能团。
Cyclization of 1,3-diaryl-3-phenylsulfanyl-1-propanols to thiochromans with the participation of [1,3]-PhS shift
Opticallyactive (3R,1RS)-3-aryl-1-phenyl-3-phenylsulfanyl-1-propanols were easily dehydrated forming mainly rac-cis-2-aryl-4-phenylthiochroman, and rac-cis-4-aryl-2-phenylthiochroman along with the corresponding trans-isomers. The observed reaction outcome (rearrangement and racemisation) apparently results from the SEAr reaction involving the unusual 1,3-phenylsulfanyl group migration. This interpretation
Preparation of thiochromans<i>via</i>thermal cyclization
作者:Anton W. Jensen、Joan Manczuk、David Nelson、Onalee Caswell、Steven A. Fleming
DOI:10.1002/jhet.5570370619
日期:2000.11
Formation of the thiochroman ringsystem is achieved by a two step synthesis that involves heating 3-thiophenyl-1-propanols or 4-thiophenyl-2-butanols in toluene with catalytic amounts of p-toluenesulfonic acid. The propanols are made by the addition of sulfur stabilized carbanions to styrene oxide, ethylene oxide, propylene oxide, and isobutylene oxide. The carbanions are generated by treatment of