Research Information System
CHEMISTRY-AN ASIAN JOURNAL, vol.2, no.2, pp.273-283, 2007 (SCI-Expanded)
Palladium-catalyzed cross-coupling of various aryl iodides with bicyclopropylidene provided isolable (1'arylallylidene)cyclopropanes, which reacted with a number of carbonyl compounds in the presence of Eu(fod)(3) under high pressure to furnish oxaspiro[2.5]octene derivatives in moderate to good yields (22-69%). The reactions of the allylidenecyclopropanes with two azo compounds as dienophiles afforded diazaspiro[2.5]octenes in high yields (82 and 99%) even at ambient pressure. When treated with nitrosobenzene, two of the allylidenecyclopro-panes gave the Diels-Alder adducts in up to 83 and 40% yield. 2,5-Diiodo-pxylene coupled twice with bicyclopropylidene, and the product underwent a twofold Diels-Alder reaction with nitrosobenzene to produce the bis(spirocyclopropaneoxazine) derivative in 88% yield. This overall transformation can be brought about in a one-pot, two-step operation by addition of the nitrosoarene to the reaction mixture immediately after formation of the allylidenecyclopropanes to furnish various 5-oxa-4-azaspiro[2.5]oct-7-ene derivatives in 22-77% yield. The coupling of methyl bicyclopropylidenecarboxylate with 2,6-dimethylphenyl iodide produced a mixture of very stable regioisomeric allylidenecyclopropane derivatives in 90% yield. The reaction of this mixture with N-phenyl-triazolinedione gave a corresponding mixture of the spirocyclopropanated heterobicycles in 61% yield.