Wani Imtiyaz Ahmad, Das Subhomoy, Mondal Shobhan, Ghorai Manas K
Department of Chemistry , Indian Institute of Technology , 208016 Kanpur , Uttar Pradesh , India.
J Org Chem. 2018 Dec 7;83(23):14553-14567. doi: 10.1021/acs.joc.8b02339. Epub 2018 Nov 27.
A highly efficient and stereoselective route to access 1,3-disubstituted 1,2,3,4-tetrahydropyrazino[1,2- a]indoles and 3,4-dihydro-1H-[1,4]oxazino[4,3- a]indoles with excellent stereoselectivity (de, ee >99%) via base mediated ring opening of aziridines/epoxides with 3-methylindoles followed by BF·OEt catalyzed Pictet-Spengler reaction is accomplished. Interestingly, PTSA promoted cyclization led to the formation of oxidized 3,4-dihydropyrazino[1,2- a]indoles in excellent yields via an unprecedented Pictet-Spengler-detosylation cascade.
通过氮丙啶/环氧化物与3-甲基吲哚的碱介导开环反应，随后进行BF·OEt催化的Pictet-Spengler反应，实现了一种高效且立体选择性的合成路线，用于制备1,3-二取代的1,2,3,4-四氢吡嗪并[1,2-a]吲哚和3,4-二氢-1H-[1,4]恶嗪并[4,3-a]吲哚，具有优异的立体选择性（非对映体过量、对映体过量>99%）。有趣的是，对甲苯磺酸（PTSA）促进的环化反应通过前所未有的Pictet-Spengler-脱甲苯磺酰化级联反应，以优异的产率导致氧化的3,4-二氢吡嗪并[1,2-a]吲哚的形成。
