The results presented in this paper confirm that the stereochemical outcome of the reversible additions of lithium (R)-methyl p-tolyl sulfoxide to N-arylidene-p-anisidines (NPMP imines) depends on: (a) the reaction conditions used and (b) the electronic properties of the arylidene moiety on the starting imine. In particular, we show that under kinetic control (-70 °C) the additions involving electron-rich N-arylidene groups occur with very high stereocontrol in favor of the (2S,RS)-diastereomers, whereas an electron-deficient group favors the opposite stereochemical outcome. Based on the observations above, a mechanistic hypothesis is proposed.
本文中呈现的结果证实,李氏(R)-甲基
对甲苯基亚砜与N-芳基
亚胺(N
PMP亚胺)之间的可逆加成反应的立体
化学结果取决于:(a)所使用的反应条件,以及(b)起始
亚胺上芳基
亚胺部分的电子特性。特别是,我们展示了在动力学控制下(-70 °C),涉及富电子N-芳基
亚胺基团的加成反应以非常高的立体选择性发生,倾向于(2S,RS)-非对映异构体,而富电子缺乏的基团则倾向于相反的立体
化学结果。基于上述观察,提出了一种机理假说。