Gao Yu-Lin, Yang Yang, Wu Chen, Xie Ming-Sheng, Guo Hai-Ming
State Key Laboratory of Antiviral Drugs, Pingyuan Laboratory, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Henan Normal University, Xinxiang, Henan, 453007, China.
Chemistry. 2024 Oct 8;30(56):e202402556. doi: 10.1002/chem.202402556. Epub 2024 Sep 12.
Despite the existence of three competing reactions for propargyloxyoxindoles, we report a chemoselectivity switch between enantioselective propargyl [2,3]-Wittig rearrangement and Conia-ene-type reactions, with suppression of the [1,2]-Wittig-type rearrangement. Using C-symmetric imidazolidine-pyrroloimidazolone pyridine as the ligand and Ni(acac) as the Lewis acid, diverse 3-hydroxy 3-substituted oxindoles containing allenyl groups were obtained in up to 98 % yield and 99 % ee via asymmetric propargyl [2,3]-Wittig rearrangement. In the presence of AgOTf-Duanphos, chiral spiro dihydrofuran oxindoles were given in up to 98 % yield and 91 % ee through a Conia-ene-type reaction.
尽管对于炔丙氧基氧化吲哚存在三种相互竞争的反应，但我们报道了对映选择性炔丙基[2,3]-维蒂希重排与柯尼亚-烯型反应之间的化学选择性转换，同时抑制了[1,2]-维蒂希型重排。使用C-对称咪唑烷-吡咯并咪唑酮吡啶作为配体，以及Ni(acac)作为路易斯酸，通过不对称炔丙基[2,3]-维蒂希重排，以高达98%的产率和99%的对映体过量得到了多种含烯丙基的3-羟基-3-取代氧化吲哚。在AgOTf-段磷存在下，通过柯尼亚-烯型反应，以高达98%的产率和91%的对映体过量得到了手性螺二氢呋喃氧化吲哚。
