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Enantiospecific Alkynylation of Alkylboronic Esters.

ABSTRACT: Enantioenriched secondary and tertiary alkyl pinacolboronic esters undergo enantiospecific deborylative alkynylation through a Zweifel-type alkenylation followed by a 1,2-elimination reaction. The process involves use of ?-lithio vinyl bromide or vinyl carbamate species, for which application to Zweifel-type reactions has not previously been explored. The resulting functionalized 1,1-disubstituted alkenes undergo facile base-mediated elimination to generate terminal alkyne products in high yield and excellent levels of enantiospecificity over a wide range of pinacolboronic ester substrates. Furthermore, along with terminal alkynes, internal and silyl-protected alkynes can be formed by simply introducing a suitable carbon- or silicon-based electrophile after the base-mediated 1,2-elimination reaction.

SUBMITTER: Wang Y

PROVIDER: S-EPMC4804747 | biostudies-literature | 2016 Mar

REPOSITORIES: biostudies-literature

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Enantiospecific Alkynylation of Alkylboronic Esters.

Wang Yahui Y Noble Adam A Myers Eddie L EL Aggarwal Varinder K VK

Angewandte Chemie (International ed. in English) 20160302 13

Enantioenriched secondary and tertiary alkyl pinacolboronic esters undergo enantiospecific deborylative alkynylation through a Zweifel-type alkenylation followed by a 1,2-elimination reaction. The process involves use of α-lithio vinyl bromide or vinyl carbamate species, for which application to Zweifel-type reactions has not previously been explored. The resulting functionalized 1,1-disubstituted alkenes undergo facile base-mediated elimination to generate terminal alkyne products in high yield ...[more]

PMID: 26934427

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