名称:
Efficient One-Pot Synthesis of α,β-Unsaturated Carbyne Complexes fac-[RuX3{⋮CC(H)CR2}(dppf)] (X = Cl, Br; R = Aryl, Alkyl; dppf = 1,1‘-Bis(diphenylphosphino)ferrocene)
摘要:
Alkenyl-carbyne complexes fac-[RuX3{equivalent to CC(H)=CR2}(dppf)] (X = Cl, Br; R = Ph, Pr-i or CR2 = C13H8) (2a-c, 3a-c) have been prepared by reaction of the bis(allyl)-ruthenium(II) derivative [Ru(eta(3)-2-C3H4Me)(2)(dppf)] (1) with the appropriate propargylic alcohol HC equivalent to CCR2(OH) in the presence of 3.5 equiv of the corresponding hydrogen halide HX. The structure of compounds fac-[RuCl3{equivalent to CC(H)=CR2}(dppf)] (R = Ph (2a) and Pr-i (2c)) has been confirmed by X-ray crystallography. Structural parameters within the alkenyl-carbyne chain in 2a,c suggest an important contribution of the zwitterionic vinylidene canonical form fac- [RuCl3{=C=C(H)-CR2}(dppf)]. Formation of complexes 2,3a-c involves the 1,3-addition of HX to the corresponding dinuclear allenylidene intermediates [{RuX(mu-X)(=C=C=CR2)(dppf)}(2)]. Such allenylidene complexes, i.e., [{RuX(mu-X)(=C=C=CR2)(dppf)}(2)] (X = Cl, Br; R = Ph or CR2 = C13H8) (4a,b, 5a,b), have been prepared and characterized by treatment of fac-[RuX3-{equivalent to CC(H)=CR2}(dppf)] (X = Cl, Br; R = Ph or CR2 = C13H8) (2a,b, 3a,b) with 1 equiv of AgSbF6, via halide abstraction and concomitant deprotonation of the alkenyl-carbyne chain.