A new and efficient method was developed to prepare alpha-phenylseleno-beta-substituted styrenes by reaction of diethyl alpha-phenylseleno benzylphosphonate with NaH and aldehydes. Selenium-lithium exchange by reaction with n-BuLi yielded the vinyl lithium species, which were captured with several electrophiles, like aldehydes and DMF, affording exclusively (Z)-allyl alcohols, and (E)-alpha-phenyl-alpha-beta-unsaturated aldehydes, respectively in good yields. The hydrolysis of the vinyl selenides in presence of TiCl4 allowed the corresponding alpha-aryl acetophenones.
Horner-Wittig reactions; vinyl selenides; transmetallation; a-b-unsaturated aldehydes; Z-allyl alcohols
