Martinez-Erro S, García-Vázquez V, Sanz-Marco A, Martín-Matute B. Stereospecific Isomerization of Allylic Halides via Ion Pairs with Induced Noncovalent Chirality.
Org Lett 2020;
22:4123-4128. [PMID:
32383608 PMCID:
PMC7497663 DOI:
10.1021/acs.orglett.0c01200]
[Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Indexed: 11/28/2022]
Abstract
A regioselective protocol for the synthesis of substituted allylic chlorides, bromides, and fluorides has been established. Remarkably, the method can be applied to the enantioselective synthesis of challenging chiral allylic chlorides. When the allylic halides are treated with the base triazabicyclodecene as the catalyst, a [1,3]-proton shift takes place, giving the corresponding vinyl halides in excellent yields with excellent Z:E ratios. Furthermore, the [1,3]-proton shift takes place with an outstanding level of chirality transfer from chiral allylic alcohols (≤98%) to give chiral trifluoromethylated vinyl chlorides.
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