Evidence of cation-coordination involvement in directing the regioselective di-inversion reaction of vicinal di-sulfonate esters
作者:Rachel Hevey、Chang-Chun Ling
DOI:10.1039/c3ob27336a
日期:——
Direct evidence has been obtained to confirm the unusual nucleophilic attack of an alkoxide at the S-center of sp3-hybridized sulfonyl esters. The unusual reaction pathway leads to S–O bond scission which is crucial for the regio- and stereoselective conversion of 2,3-di-O-sulfonates of 4,6-O-benzylidene-β-D-galactopyranosides into β-D-idopyranosides. In addition, strong evidence has been provided
已经获得直接证据来证实醇盐在sp 3-杂交磺酰基酯的S-中心的异常亲核攻击。这种不寻常的反应途径导致S-O键断裂这对于区域选择性和立体选择性转化的2,3-二-关键Ö -sulfonates 4,6-的ø -亚苄基- β- d -galactopyranosides成β- d -吡喃吡喃糖苷。另外,已经提供了强有力的证据来阐明碱抗衡阳离子在转化中的作用。据认为,阳离子通过与磺酸酯中的氧配位而影响反应速率。顺式取向的相邻环氧的存在-关系极大地增强了磺酰基酯的反应性。