CH3CH=CH2
(C6H5)3P=O
Try recalling wittig Reaction.
Wittig reaction
This method involves a convenient method of converting aldehydes and ketones into alkenes by using a special class of compounds called phosphorous yieldes, also called wittig reagent. Primary or secondary alkyl halide is first treated with triphenyl phosphine'e the phosphonium halide produced in the above reaction is converted into phosphorane by adding a rang base like C6H5Li on n-C3H9-Li . phosphorane is stabilized by resonance.