Stereochemistry of SN2′ Additions to Acyclic Vinyloxiranes

James A. Marshall, Joseph D. Trometer, Bruce E. Blough, Thomas D Crute

Research output: Contribution to journalArticle

48 Scopus citations

Abstract

The isomeric trans-(E)-, trans-(Z)-, cis-(E)-, and cis-(Z)-vinyloxiranes 7, 9, 17, and 19 were prepared from 2- (benzyloxy)ethanol by sequential Swern-Wittig or Swern-Horner-Emmons propionate condensation, DIBAH reduction, Sharpless epoxidation, Swern oxidation, Wittig or Horner-Emmons acetate condensation, and a second DIBAH reduction. Addition of lithium dimethylcuprate and lithium methylcyanocuprate to these epoxides in THF-ether at -20 to 0 °C afforded the allylic alcohols 22, 25, ent-23, and ent-22 as the major products. These products are formed by anti addition to the lower energy conformer (s-trans for 7, 17, and 19 and s-cis for 9) of the respective vinyloxirane. The conformational preferences of transition-state-like geometries of the vinyloxiranes, calculated with the aid of Still’s MacroModel program, were in agreement with the observed trends.

Original languageEnglish (US)
Pages (from-to)4274-4282
Number of pages9
JournalJournal of Organic Chemistry
Volume53
Issue number18
DOIs
StatePublished - Aug 1 1988
Externally publishedYes

ASJC Scopus subject areas

  • Organic Chemistry

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