Ding Y, Kuang J, Xiao X, Wang L, Ma Y. Environmentally Benign Synthesis of Quinoline-Spiroquinazolinones by Iron-Catalyzed Dehydrogenative [4 + 2] Cycloaddition of Secondary/Tertiary Anilines and 4-Methylene-quinazolinones.
J Org Chem 2021;
86:12257-12266. [PMID:
34387487 DOI:
10.1021/acs.joc.1c01602]
[Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report an efficient iron-catalyzed cross-dehydrogenative coupling [4 + 2] annulation of secondary/tertiary anilines with quinazolinones to generate quinoline-spiroquinzolinones. The reaction proceeds smoothly with a relatively broad variety of functional groups, a cheap transition metal catalyst (FeCl3), and environmentally friendly oxidant (H2O2/O2) under mild reaction conditions. Creatively, N-methylanilines are employed for the first time for the cycloaddition as both methyl and methylene sources attached to the N atom of tetrahydroquinolines.
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