Synthesis of Bicyclo[4.1.0]tetrahydropyridazines by a Sequential [4 + 2] and [1 + 2] Annulation Reaction of Azoalkenes and Crotonate-Derived Sulfur Ylides

Wenhao Yin; Ling Fang; Zhiyong Wang; Fang Gao; Zhefeng Li; Zhiyong Wang

doi:10.1021/acs.orglett.9b02661

Synthesis of Bicyclo[4.1.0]tetrahydropyridazines by a Sequential [4 + 2] and [1 + 2] Annulation Reaction of Azoalkenes and Crotonate-Derived Sulfur Ylides

Org Lett. 2019 Sep 20;21(18):7361-7364. doi: 10.1021/acs.orglett.9b02661. Epub 2019 Sep 4.

Authors

Wenhao Yin¹, Ling Fang², Zhiyong Wang¹, Fang Gao¹, Zhefeng Li¹, Zhiyong Wang¹

Affiliations

¹ School of Chemistry and Chemical Engineering , Chongqing University , Chongqing 401331 , China.
² College of Environment and Resources , Chongqing Technology and Business University , Chongqing 400067 , China.

PMID: 31483675
DOI: 10.1021/acs.orglett.9b02661

Abstract

The base-induced unprecedented tandem [4 + 2] and [1 + 2] annulation reaction of in situ formed 1,2-diaza-1,3-dienes and crotonate-derived sulfur ylides is reported. This protocol provides a novel and practical method for the synthesis of cyclopropane-fused tetrahydropyridazines with a quaternary carbon center in synthetically useful yield. In this tandem reaction, three new bonds were formed in one pot, and the crotonate-derived sulfur ylide serves as a C3 synthon.