Beta-carotene is synthesized from vitamin A using this reaction in which an aldehyde or ketone reacts with a phosphonium ylide to form an alkene.
Giving the same products as the Peterson reaction, unlike the Knoevenagel and aldol reactions, it is stereoselective and regiospecific.  Beta-carotene is synthesized from vitamin A using this reaction in which an aldehyde or ketone reacts with a phosphonium ylide to form an alkene. For ten points, name this eponymous reaction which won its German discoverer a share of a Nobel Prize.
Giving the same products as the Peterson reaction, unlike the Knoevenagel and aldol reactions, it is stereoselective and regiospecific.  
Wittig reaction