The effect of various reaction conditions on the proportions of cis and trans olefinic products' obtained from the Wittig reaction of stabilized ylids 1 and 10 with acetaldehyde and chloroacetaldehyde has been studied. The highest proportion of cis isomer was obtained by the use of the protonic solvent, methanol. Solutions of lithium salts were less effective and suspensions of lithium salts were without effect in enhancing the proportion of cis olefin in ...
