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A Single-Flask Synthesis of ?-Alkylidene and ?-Benzylidene Lactones from Ethoxyacetylene, Epoxides/Oxetanes, and Carbonyl Compounds.

ABSTRACT: Low temperature treatment of (ethoxyethynyl)lithium with epoxides or oxetanes in the presence of BF3•OEt2, followed by addition of aldehydes or ketones and warming to room temperature, affords structurally diverse five- and six-membered ?-alkylidene and ?-benzylidene lactones (5) in good to excellent yields. This one-pot process, in which three new carbon-carbon bonds and a ring are formed, affords substituted ?,?-unsaturated lactones of predominantly Z-configuration. The reaction likely occurs via alkyne-carbonyl metathesis of a hydroxy-ynol ether intermediate, acid-promoted alkene E- to Z-isomerization, and lactonization.

SUBMITTER: Ng K

PROVIDER: S-EPMC4698893 | biostudies-other | 2016 Jan

REPOSITORIES: biostudies-other

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A Single-Flask Synthesis of α-Alkylidene and α-Benzylidene Lactones from Ethoxyacetylene, Epoxides/Oxetanes, and Carbonyl Compounds.

Ng Kevin K Tran Vincent V Minehan Thomas T

Tetrahedron letters 20160101 3

Low temperature treatment of (ethoxyethynyl)lithium with epoxides or oxetanes in the presence of BF3•OEt2, followed by addition of aldehydes or ketones and warming to room temperature, affords structurally diverse five- and six-membered α-alkylidene and α-benzylidene lactones (5) in good to excellent yields. This one-pot process, in which three new carbon-carbon bonds and a ring are formed, affords substituted α,β-unsaturated lactones of predominantly Z-config ...[more]

PMID: 26744547

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