Acid/base-controlled chemodivergent synthesis of two differently functionalized tetrahydroimidazo[1,2-a]pyridinesElectronic supplementary information (ESI) available: Experimental procedures, full spectroscopic data for all new compounds, and crystal data for 4a, 5c and 6h (CIF). CCDC 858868, 878006 and 1003512. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c5ra13395e

• Main Authors: Guo, Wei-Si, Xin, Xing, Zhao, Ke-Long, Wen, Li-Rong, Li, Ming
• Format: Article
• Language: English
• ISSN: 2046-2069
• DOI: 10.1039/c5ra13395e

A new approach for the facile chemodivergent synthesis of tetrahydroimidazo[1,2- a ]pyridines from β -ketothioamides, aldehydes and heterocyclic ketene aminals is described. In the presence of a base, an unprecedented ring-opening, tautomerization, recyclization cascade is observed and H 2 S eliminated tetrahydroimidazo[1,2- a ]pyridines were formed in good yields. With catalytic amounts of acid, another type of different substituted tetrahydroimidazo[1,2- a ]pyridines were obtained through dehydration. Two differently substituted type of imidazo[1,2- a ]pyridine derivatives were synthesized chemodivergently using β -ketothioamides, aldehydes and heterocyclic ketene aminals through acid/base regulation.