Stereoselective Synthesis of (2Z)-2,4-Dienamides via NBS-Mediated Allyloxyl Addition-Claisen Rearrangement-Dehydrobromination Cascade Reaction of Ynsulfonamides

Runbo Ding; Yun Li; Cheng Tao; Bin Cheng; Hongbin Zhai

doi:10.1021/acs.orglett.5b01859

Stereoselective Synthesis of (2Z)-2,4-Dienamides via NBS-Mediated Allyloxyl Addition-Claisen Rearrangement-Dehydrobromination Cascade Reaction of Ynsulfonamides

Org Lett. 2015 Aug 21;17(16):3994-7. doi: 10.1021/acs.orglett.5b01859. Epub 2015 Aug 13.

Authors

Runbo Ding¹, Yun Li¹, Cheng Tao¹, Bin Cheng¹, Hongbin Zhai^{1

2}

Affiliations

¹ †The State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou, 730000, China.
² ‡Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300071, China.

PMID: 26270391
DOI: 10.1021/acs.orglett.5b01859

Abstract

An NBS-promoted allyloxyl addition-Claisen rearrangement-dehydrobromination cascade reaction has been developed. More than 20 substituted alkynylsulfonamides were reacted with allyl alcohols to generate (2Z)-2,4-dienamides in moderate to high yields. A mechanistic model has been proposed to account for the overall reaction sequence including the stereochemical outcome. Theoretical calculations suggested that a [3,3] sigmatropic rearrangement be the rate-limiting step.