Formation of indene derivatives from bis(cyclopentadienyl)titanacyclopentadienes with alkyl group migration via carbon-carbon bond cleavage.

A novel type of migration of an alkyl group in the formation of indene derivatives from titanacyclopentadienes was found. When titanacyclopentadienes with four alkyl groups were heated at 50 degrees C in THF for 24 h under nitrogen, titanium dihydroindene complexes were formed. Oxidation of the dihydroindene complexes with oxygen or alkyl halides afforded indene derivatives with unusual migration of one alkyl group at the diene moiety to the five-membered ring of the indene derivatives.

Ruthenium-catalyzed ROM-RCM of cycloalkene-yne.

[formula: see text] ROM-RCM (ring-opening and ring-closing metatheses) of cycloalkene-yne was demonstrated using a second-generation ruthenium complex. When cycloalkene bearing the alkyne moiety at the C-1 position was reacted with a ruthenium-carbene complex under an atmosphere of ethylene, ROM-RCM proceeded smoothly to give bicyclic compound and/or dimeric compound in good yields.