BEHAVIOR OF Z-S-CIS-FERROCENYL-1,3-DIENES AND E-S-CIS-FERROCENYL-1,3-DIENES IN CYCLOADDITION AND DIMERIZATION REACTIONS

Z-3-Ferrocenylmethylene-2-methylenecamphane and E-2-ferrocenylmethylen e- 3-methylenequinuclidine were synthesized by isomerization of the co rresponding isomeric E- and Z-1,3-dienes in an acidic medium. The dien es obtained form [4+2]-cycloaddition endo-adducts with N-phenylmaleimi de, do not form cyclodimers upon thermal or acid-catalyzed [4+2]-cyclo dimerization, and add lene-1,2,7,7-tetramethylbicyclo[2.2.1]hept-2-yli um and thylene-3-methyl-1-azoniabicyclo[2.2.1]oct-3-ylium salts, respe ctively, at the terminal methylene group to give linear addition produ cts. The latter undergo fragmentation on treatment with HBF4 to form t he corresponding carbocation tetrafluroborates.