Catalytic [6π+2π]-cycloaddition of Si-containing alkynes to 7-substituted 1,3,5-cycloheptatrienes under the action of Ti(acac)2Cl2–Et2AlCl

• For the first time the Ti-catalyzed cyclocodimerization of substituted cycloheptatrienes with Si-containing alkynes was developed.
• Efficient syntheses of novel substituted bicyclo[4.2.1]nona-2,4,7-trienes.
• The reaction mechanism was studied through quantum chemical modeling.
• The structures of all novel compounds were confirmed by NMR measurements.

The reaction of 7-alkyl(allyl,phenyl)-1,3,5-cycloheptatrienes with Si-containing alkynes catalyzed by the two-component Ti(acac)2Cl2–Et2AlCl system, resulting in the formation of substituted bicyclo[4.2.1]nona-2,4,7-trienes in high yields, was accomplished. The structures of the obtained compounds were confirmed by 1H, 13C NMR spectroscopy. The reaction mechanism was studied through quantum chemical modeling of the cycloheptatriene and acetylene interaction with TiCl4–Et2AlCl system at the B3LYP/6-31G(d) level.

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