(Ss)-5-ethoxy-3-p-tolylsulfinylfuran-2(5H)-ones as chiral dipolarophiles: First asymmetric cycloaddition of diazomethane to vinyl sulfoxides
作者:Jose L. García Ruano、Alberto Fraile、M. Rosario Martín
DOI:10.1016/0957-4166(96)00233-9
日期:1996.7
Cycloadditions of diazomethane to (Ss)-5-ethoxy-3-p-tolylsulfinylfuran-2(5H)-ones 1a–b and their corresponding 4-methyl derivatives 3a–b, proceeds in quantitative yields, to give enantiomerically pure 3H,6H,3a,6a-dihydrofuro[3,4-c]pyrazol-4-ones 2a–b and 4a–b, respectively. The sulfinyl group at C-3 strongly increases both the reactivity and the π-facial selectivity. The dipole approach mode is determined
重氮甲烷与(S s)-5-乙氧基-3-对甲苯磺酰呋喃-2(5 H)-ones 1a–b及其相应的4-甲基衍生物3a–b的环加成反应以定量产率进行,得到对映体纯的3 H,6 H,3a,6a-二氢呋喃[3,4-c]吡唑-4-酮2a–b和4a–b。C-3处的亚磺酰基会大大提高反应性和π面选择性。偶极接近模式由亚磺酰基的构型决定。吡唑啉2a或2b的热解得到甲基衍生物3a或3b的产量极高。