Pan LN, Sun J, Liu XY, Yan CG. Efficient construction of diverse spiro[indoline-3,4'-pyrrolo[3,4-
b]pyridines]
via [3 + 3] cycloaddition of MBH carbonates of isatins with β-enamino maleimides.
Org Biomol Chem 2022;
20:7099-7104. [PMID:
36040323 DOI:
10.1039/d2ob01257j]
[Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
An efficient method to construct unique spiro[indoline-3,4'-pyrrolo[3,4-b]pyridines] was successfully developed via a DABCO promoted formal [3 + 3] cycloaddition reaction of MBH carbonates of isatins with β-enamino maleimides in acetonitrile at room temperature. This reaction afforded multifunctionalized spiro[indoline-3,4'-pyrrolo[3,4-b]pyridines] and spiro[dipyrrolo[3,4-b:3',4'-e]pyridine-8,3'-indolines] in good yields and with lower diastereoselectivity. The relative configuration of the two diasteromers of the spiro compounds was clearly elucidated by the determination of eight single crystal structures.
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