N-heterocyclic carbene-promoted annulation reaction of allenals with chalcones: synthesis of polysubstituted pyranyl aldehydes

Dengke Ma; Youai Qiu; Jianxin Dai; Chunling Fu; Shengming Ma

doi:10.1021/ol5021509

N-heterocyclic carbene-promoted annulation reaction of allenals with chalcones: synthesis of polysubstituted pyranyl aldehydes

Org Lett. 2014 Sep 19;16(18):4742-5. doi: 10.1021/ol5021509. Epub 2014 Sep 4.

Authors

Dengke Ma¹, Youai Qiu, Jianxin Dai, Chunling Fu, Shengming Ma

Affiliation

¹ Laboratory of Molecular Recognition and Synthesis, Department of Chemistry, Zhejiang University , Hangzhou 310027, Zhejiang, People's Republic of China.

PMID: 25188791
DOI: 10.1021/ol5021509

Abstract

A general N-heterocyclic carbene (NHC)-promoted annulation reaction of allenals with chalcones affording polysubstituted pyranyl aldehydes has been developed. Three mechanistic possible pathways have been proposed. The NHC attacks the center carbon of allenals or acts as a base for deprotonation and then undergoes a 1,4-addition with chalcones, followed by sequential reactions giving the final products.