trans-Form prepd by Clemmensen reduction of benzoin: Shriner, Berger, Org. Synth. coll. vol. III, 786 (1955); cis-form by copper-chromite decarboxylation of α-phenylcinnamic acid: Buckles, Wheeler, ibid. coll. vol. IV, 857 (1963). Synthesis of cis- and trans-forms by the Wittig reaction and by decarboxylation of phenylcinnamic acids: Wheeler, Batlle de Pabon, J. Org. Chem. 30, 1473 (1965).