Yang T, Nie ZW, Su MD, Li H, Luo WP, Liu Q, Guo CC. Unexpected Annulation between 2-Aminobenzyl Alcohols and Benzaldehydes in the Presence of DMSO: Regioselective Synthesis of Substituted Quinolines.
J Org Chem 2021;
86:15228-15241. [PMID:
34632772 DOI:
10.1021/acs.joc.1c01850]
[Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
An unexpected annulation among 2-aminobenzyl alcohols, benzaldehydes, and DMSO to quinolines has been disclosed. For the reported annulation between 2-aminobenzyl alcohols and benzaldehydes, the change of the solvent from toluene to DMSO led to the change of the product from the diheteroatomic cyclic benzoxazines to monoheteroatomic cyclic quinolines. This annulation can be used to synthesize regioselectively different substituted quinolines by the choice of different 2-amino alcohols, aldehydes, and sulfoxides as substrates. Interestingly, introducing substituent groups to the α-position of sulfoxides resulted in the interchange of the positions between benzaldehydes and sulfoxides in the product quinolines. On the basis of the control experiments and literatures, a plausible mechanism for this annulation was proposed.
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