Ruthenium-catalyzed cyclization of 2-alkyl-1-ethynylbenzenes via a 1,5-hydrogen shift of ruthenium-vinylidene intermediates.
Catalytic cyclization of 2-alkyl-1-ethynylbenzene derivatives was implemented by TpRuPPh3(CH3CN)2PF6 (10 mol %) in hot toluene (105 degrees C, 36-100 h) to form 1-substituted-1H-indene and 1-indanone products; such cyclizations proceeded more efficiently for substrates bearing electron-rich benzenes. We propose that the cyclization mechanism involves a 1,5-hydrogen shift of initial metal-vinylidene intermediate.
Odedra
Arjan
A
Department of Chemistry, National Tsing-Hua University, Hsinchu, Taiwan, 30043, Republic of China.
Datta
Swarup
S
Liu
Rai-Shung
RS