115827-47-9Relevant academic research and scientific papers
Stereochemistry of SN2' Additions to Acyclic Vinyloxiranes
Marshall, James A.,Trometer, Joseph D.,Blough, Bruce E.,Crute, Thomas D.
, p. 4274 - 4282 (1988)
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-eather at -20 to 0 deg 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 vinyl-oxiranes, calculated with the aid of Still's MACROMODEL program, were in agreement with the observed trends.
