The Diels-Alder reactions between styrene and trans-penta-1,3 -diene, methyl 2-trans,4-penta- dienoate and dimethyl 2-trans,4-trans-hexadienedioate are described.The structure of the following adducts was determined by means of IR and NMR spectrometry: trans-3-methyl-4-phenyl-cyclohex-1- ene,cis-3-methyl-4-phenyl-cyclohex-1-ene,trans-3-methyl-5-phenyl-cyclohex-1-ene,cis-3-methyl-5-phenyl- -cyclohex-1-ene, trans-3-carbomethoxy-4-phenyl-cyclohex-1-ene, cis-3-carbomethoxy-4-phenyl-cyclohex- 1-ene, 3-carbomethoxy-cis-4-phenyl-cis-6-carbomethoxy-cyclohex-1-ene and 3-carbomethoxy-trans-4- phenyl-cis-6-carbomethoxy-cyclohex-1-ene. © 1969.