Selective production of 1-arylalkenes
Moderately activated benzenoid compounds undergo alkylation with allylic chlorides and particularly allylic alcohols over solid acid catalysts. Acidic K10 clay is the optimal catalyst and allows almost exclusive attack at the terminal position of the intermediate allyl cation to yield 1-aryl-2-alkenes. Catalytic hydrogenation quantitatively yields the corresponding 1-arylalkanes. Phenol also reacts readily but gives a significant quantity (ca. 12%) of 3-aryl-1-butene along with 1-aryl-2-butene.