Ruthenium(II)-catalyzed cyclization of azabenzonorbornadienes with alkynes.
The ruthenium-catalyzed cyclization of azabenzonorbornadienes with alkynes leads to an unanticipated dihydrobenzoindole framework. Depending on the structure of the alkyne and the Ru catalyst, either a dihydrobenzoindole and/or a [2+2] cycloaddition product could be formed. Cp*Ru(COD)Cl was found to be an active catalyst for the cyclization of an azabenzonorbornadiene with a propargylic alcohol to produce the dihydrobenz[g]indole as a single regio and stereoisomer in good yield. For other alkynes, selective formation of the dihydrobenz[g]indole is possible by using a cationic Ru catalyst, [Cp*Ru(CH3CN)3]PF6.
Burton
Ryan R
RR
Guelph-Waterloo Centre for Graduate Work in Chemistry and Biochemistry, Department of Chemistry, University of Guelph, Guelph, Ontario, Canada N1G 2W1.
Tam
William
W