Chen S, You B, Zhang T, Li M, Gu Y. Diversity-Oriented Metal-Free Synthesis of Nitrogen-Containing Heterocycles Using Atropaldehyde Acetals as a Dual C3/C2-Synthon.
CHEMSUSCHEM 2022;
15:e202201301. [PMID:
35909080 DOI:
10.1002/cssc.202201301]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Revised: 07/26/2022] [Indexed: 06/15/2023]
Abstract
A highly efficient and elegant diversity-oriented reaction paradigm employing atropaldehyde acetals as new dual C2/C3 synthons was developed under metal-free conditions using glycine esters as the counterpart reagents, which allowed rapid synthesis of two important nitrogen-containing heterocycles, pyrrolo[1,2-a]quinolines and 3,5-diarylpyridines. The divergent products are subtly controlled by the manipulation of the substitutional groups of glycine esters. When a N-arylglycine ester was used, pyrrolo[1,2-a]quinolines can be formed through cascade oxidative C-C cleavage/multiple cyclization. Instead, N-benzylglycine ester as the counter-reagent led to the synthesis of 3,5-diarylpyridines via two key C-N cleavages. Mild conditions, broad substrate scope, scalability and environmentally acceptable organic solvents rendered this method practical and attractive.
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