Reactions of Ruthenium Complexes Containing Pentatetraenylidene Ligand

Two ruthenium acetylide complexes [Ru]−C≡C−C≡C−C(OR)(C 3 H 5 ) 2 ( 2 , R=H and 2 a , R=CH 3 ; [Ru]=Cp(PPh 3 ) 2 Ru) each with two cyclopropyl rings were synthesized from TMS−C≡C−C≡C−C(OH)(C 3 H 5 ) 2 ( 1 ; TMS=trimethylsilyl). Treatments of 2 and 2 a with allyl halide in the presence of KPF 6 afforded the vinylidene complexes  3 and 3 a , respectively. When NH 4 PF 6 was used, instead of KPF 6 , additional ring‐opening reaction took place on one of the three‐membered ring. Treatment of [Ru]Cl with 1,3‐butadiyne ( 6 ), bearing an epoxide ring, afforded acetylide complex  7 with a furyl ring. Treatment of 2 a with Ph 3 CPF 6 presumably afforded pentatetraenylidene complex {[Ru]=C=C=C=C=C(C 3 H 5 ) 2 }[PF 6 ] ( 10 ), which was not isolated. Additions of various alcohols in a solution of 10 generated a number of disubstituted allenylidene complexes {[Ru]=C=C=C(OR)−C=C(C 3 H 5 ) 2 }[PF 6 ] ( 11 ). Treatment of 11 with K 2 CO 3 afforded the acetylide complex  12 bearing a carbonyl group, characterized by single X‐ray diffraction analysis. Addition of a primary amine to 10 caused cleavage of the farthermost C=C bond and several allenylidene complexes {[Ru]=C=C=C(Me)(NHR)}[PF 6 ] ( 18 ) were isolated.