α-甲锡烷基苯硫醚的异丙苯溶液在 -78 °C 下用 n-BuLi 和双(恶唑啉)-iPr 处理,随后用二苯甲酮处理,得到 99% ee 的产物。我们证实α-锂硫苄基苯硫醚的反应通过动态动力学拆分途径进行。α-锂硫苄基2-吡啶基硫醚的对映选择性反应得到的产物与苄基苯基硫醚反应得到的产物立体化学相反。我们证实该反应通过动态热力学拆分途径进行,在该途径中,与亲电子试剂的反应比非对映体复合物之间的相互转化进行得更快。
Enantioselective S−H Insertion Reactions of α‐Carbonyl Sulfoxonium Ylides
作者:Patrícia B. Momo、Alexandria N. Leveille、Elliot H. E. Farrar、Matthew N. Grayson、Anita E. Mattson、Antonio C. B. Burtoloso
DOI:10.1002/anie.202005563
日期:2020.9
The first example of enantioselectiveS−Hinsertionreactions of sulfoxoniumylides is reported. Under the influence of thiourea catalysis, excellent levels of enantiocontrol (up to 95 % ee) and yields (up to 97 %) are achieved for 31 examples in S−Hinsertionreactions of aryl thiols and α‐carbonylsulfoxoniumylides.
Too unstable for asymmetric deprotonation, alpha-sulfenyl carbanions can undergo asymmetric substitution reactions with high stereoselectivity [Eq. (1)]. The key to the asymmetric induction is the dynamic kinetic resolution of the complex formed between the organolithium compound and a chiral ligand, the most effective of which were bisoxazoline derivatives.