Chemistry of heterocyclic ketene aminals: construction of imidazo(pyrido)[1,2-a]pyridines and imidazo(pyrido)[3,2,1-ij][1,8]naphthyridines via DABCO-catalyzed tandem annulations

Ming Li; Zhong-Min Zhou; Li-Rong Wen; Zhong-Xuan Qiu

doi:10.1021/jo102167g

Chemistry of heterocyclic ketene aminals: construction of imidazo(pyrido)[1,2-a]pyridines and imidazo(pyrido)[3,2,1-ij][1,8]naphthyridines via DABCO-catalyzed tandem annulations

J Org Chem. 2011 May 6;76(9):3054-63. doi: 10.1021/jo102167g. Epub 2011 Apr 14.

Authors

Ming Li¹, Zhong-Min Zhou, Li-Rong Wen, Zhong-Xuan Qiu

Affiliation

¹ State Key Laboratory Base of Eco-Chemical Engineering, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, PR China. liming928@qust.edu.cn

PMID: 21449612
DOI: 10.1021/jo102167g

Abstract

2-(2-Chloroaroyl)methyleneimidazolidines with four reactive sites show fascinating structural features and could be used as a new strategy for the synthesis of novel heterocycles. This paper presents our new findings in the reaction of 2-(2-chloroaroyl)methyleneimidazolidines with allenic esters affording functionalized imidazo(pyrido)[1,2-a]pyridines via DABCO-catalyzed tandem annulations. Of particular significance is the incorporation of an o-halo group into the aryl ring of 2-benzoylmethylene-imidazolidines to set up a convenient and general way for constructing unusual imidazo(pyrido)[3,2,1-ij][1,8]naphthyridines.