Free-radical cyclization of enantiomerically enriched 2-p-tolylthio derivatives of 2-allylcyclohexanones with Mn(III): asymmetric synthesis of bridged bicyclic ketones and thiochroman-3-ones
作者:J.L Garcı́a-Ruano、A Rumbero
DOI:10.1016/s0957-4166(99)00467-x
日期:1999.11
enriched 2-allyl-2-(p-tolylsulfonyl)-cyclohexanone 4 and 2-allyl-2-(p-tolylsulfenyl)cyclohexanone 9 are reported. The observed chemoselectivity (reaction on the allylic double bond yielding bridged bicyclic ketones vs. reaction on the aromatic ring of the p-tolyl group affording thiochroman-3-ones) depends on the sulfur function (sulfone or thioether, respectively), which determines the electronic density
报道了对映体富集的2-烯丙基-2-(对甲苯磺酰基)-环己酮4和2-烯丙基-2-(对甲苯磺酰基)环己酮9的基于Mn(III)的氧化分子内环化。观察到的化学选择性(在烯丙基双键上生成桥联双环酮的反应与在对甲苯基上生成硫代色烷-3-酮的芳香环上的反应)分别取决于硫官能团(分别为砜或硫醚),这决定了对甲苯基环的电子密度和起始化合物的构象偏好。C-2上取代基的性质与内/外相关 环化的选择性以及烯酮形成中的区域选择性。