Kinetic and thermodynamic stereocontrol in the atroposelective formation of sulfoxides by oxidation of 2-sulfanyl-1-naphthamides
作者:Mark S. Betson、Jonathan Clayden、Madeleine Helliwell、David Mitjans
DOI:10.1039/b511452g
日期:——
diastereoselectivity. NMR studies and oxidations of chiral benzamides however indicate that the kinetic selectivity of the oxidation is in fact relatively poor, and that the final diastereoisomeric ratio (typically >99:1) is under thermodynamic control, with relatively unhindered Ar-CO rotation readily converting the less stable to the more stable product diastereoisomer. Molecular mechanics indicates that
带有2-硫烷基的阻转异构芳族酰胺显然被m-CPBA氧化为相应的亚砜,具有非常高的非对映选择性。NMR研究和手性苯甲酰胺的氧化表明,氧化的动力学选择性实际上相对较差,并且最终的非对映异构体比率(通常> 99:1)处于热力学控制下,相对不受阻碍的Ar-CO旋转很容易转化为对于较稳定的产物非对映异构体,稳定性较差。分子力学表明,热力学非对映选择性主要是由C = O和SO偶极之间的静电排斥引起的。