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Stereoselective Synthesis of Trisubstituted Vinyl Bromides by Addition of Alkynes to Oxocarbenium Ions.

ABSTRACT: We have developed an efficient method for the synthesis of (E)-trisubstituted vinyl bromides via a Friedel-Crafts-type addition of alkynes to oxocarbenium ions formed in situ from acetals. The success of this reaction relies on identification of MgBr2·OEt2 as both a Lewis acid promoter and bromide source. This reaction employs simple, inexpensive starting materials and proceeds under mild conditions to allow the preparation of a range of vinyl bromide products in high yields and E:Z selectivities. Furthermore, the vinyl bromide products also contain an allylic ether functional group. Both the vinyl bromide and allylic ether are effective handles for the elaboration of these useful synthetic intermediates.

SUBMITTER: Ehle AR

PROVIDER: S-EPMC4961304 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature

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Stereoselective Synthesis of Trisubstituted Vinyl Bromides by Addition of Alkynes to Oxocarbenium Ions.

Ehle Andrew R AR Morris Melissa G MG Klebon Bryan D BD Yap Glenn P A GP Watson Mary P MP

Synlett : accounts and rapid communications in synthetic organic chemistry 20150914 19

We have developed an efficient method for the synthesis of (E)-trisubstituted vinyl bromides via a Friedel-Crafts-type addition of alkynes to oxocarbenium ions formed in situ from acetals. The success of this reaction relies on identification of MgBr<sub>2</sub>·OEt<sub>2</sub> as both a Lewis acid promoter and bromide source. This reaction employs simple, inexpensive starting materials and proceeds under mild conditions to allow the preparation of a range of vinyl bromide products in high yield ...[more]

PMID: 27482143

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