Wani IA, Sk S, Mal A, Sengupta A, Ghorai MK. Stereoselective Routes to Hexahydropyrroloindoles and Tetrahydropyrroloquinolines from Activated Aziridines and Electron Deficient 3
H-Indoles.
Org Lett 2022;
24:7867-7872. [PMID:
36094406 DOI:
10.1021/acs.orglett.2c02354]
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Abstract
An unprecedented and novel synthetic route to hexahydropyrrolo[2,3-b]indoles bearing cis-contiguous stereocenters with excellent stereoselectivities (ee of >99%, dr of ≤99:1) has been disclosed that proceeds through the ring opening of activated aziridines with electron deficient 4-substituted indoles followed by a novel cyclization in a domino fashion, thereby obviating the use of 3-substituted indoles as the prerequisite nucleophile. Another efficient synthetic route to tetrahydropyrrolo[4,3,2-de]quinolines in excellent yields (≤93%) and excellent enantioselectivity (ee of >99%) has been established via ring opening of activated aziridines with 4-bromo-1-methyl-1H-indole at relatively higher temperatures followed by Cu(I)-catalyzed intramolecular C-N cyclization in the same pot. The stability and the formation of products at different temperatures are explained by computational studies.
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