“…4-methyI-l-phenyl-l,3-butadiene (37), methyl 4-phenyl-l,3-butadiene-1carboxylate (36), alloocimene (13), eleostearic acids (24), 1,2,4-triethylnaphthalene (188), 1-vinylcyclohexene (193), 1,2dimethyl-1,3-butadiene (193) Furan (194) 1.2-Dimethylene-3,5-cyclohexadiene (113) Cyclopentadiene (9,218) 1.3-Butadiene (307) Cyclopentadiene (9,224), 1,3-cyclohexadiene (9), anthracene (76), 1-vinylnaphthalene (77), 3,4-dihydro-6-methoxy-2-vinylnaphthalene (75,161), 1-acetoxy-1,3-butadiene (193) Cyclopentadiene (47) Cyclopentadiene ( 61 249), vinylacrylic acid (303), 3,4dihydro -6 -methoxy-1 -vinylnaphthalene (251), 3-ethoxy-1,3-pentadiene (99, 261) 1.3-Butadiene (308), piperylene ( 104 In addition to the reactions cited in table 2, there are a number of cases in which stereoisomeric dienophiles lead to stereoisomeric adducts, but for which retention of configuration, while almost certain, has not been specifically proved. Among these are the addition of cis-and irans-dibenzoylethylenes to cyclopentadiene (1), the addition of maleic and fumaric acid derivatives to 2,5-dimethyl-3,4-diphenylcyclopentadienone (64) and di(l-cyclohexenyl)acetylene ( 111), the addition of cis-and íroros-o-methoxycinnamic acids to 2,3-dimethyl-1,3-butadiene (2), and the addition of hexachlorocyclopentadiene to cis-and trans-cyclooctenes and cis,cisand trans,trans-1,5-cyclooctadienes (311).…”