Cyclopropenation and Related Reactions of Ruthenium Vinylidene Complexes

Abstract

Facile deprotonation of a number of cationic ruthenium vinylidene complexes, followed by cyclopropenation, is accomplished in acetone. The deprotonation of [Ru]dCd(Ph)CH 2 R + , ([Ru] ) (η 5 -C 5 H 5 )(PPh 3 ) 2 Ru) by n-Bu 4 -NOH induces a novel cyclization reaction and yields the neutral cyclopropenyl complexes [Ru]-CdC(Ph)CHR (3b, R ) CN; 3c, R ) Ph; 3d, R ) CHdCH 2 ; 3e, R ) CHdCMe 2 ). Complex [Ru]-CdC(C 6 H 9 )CHCN + (3k) is similarly prepared. Protonation of 3b-3e regenerates the corresponding vinylidene complexes. Deprotonation of [Ru]dCdC(Ph)CH 2 COOMe + (2h) by n-Bu 4 NOH induces a different type of cyclization and yields the neutral furan complex [Ru]-CdC(Ph)CHdC(O)OMe (4h). The cyclopropenyl complex containing a methoxy substituent cannot be prepared from [Ru]dCdC(Ph)CH 2 OCH 3 + (2i), but Fof n-Bu 4 NF attacks the CR of 2i to produce the unstable vinyl complex [Ru]C(F)dC(Ph)CH 2 OCH 3 (5). Complex [Ru]-CdC(Ph)C(CN)OCH 3 (9b) was indirectly prepared from the addition of TCNQ to 3b, giving [Ru]dCdC(Ph)CH(CN)TCNQ (6b) followed by methanolysis. Unlike 3, complex 9b is not converted to vinylidene complex, instead, removal of the methoxy substituent by acid gives theis similarly prepared from 4h via a TCNQ complex 6h followed by a methoxy-substituted complex 9h. In the presence of allyl iodide, opening of the three-membered ring of 3b, followed by a subsequent oxidative coupling reaction, gives a dimeric dicationic product {[Ru]dCdC(Ph)-CHCN} 2 2+ (11). Proton abstraction of 11 by n-Bu 4 -NF gives the biscyclopropenyl complex {[Ru]-CdC(Ph)CCN} 2 (12). Molecular structures of complexes 3b, 3f, 4h, 6b, 9b, and 11 have been confirmed by X-ray diffraction analysis.

Reactivity of Ruthenium Vinylidene Complexes Containing Indenyl/dppe Ligands and Unsaturated Bonds at Cd with Trimethylsilyl Azide

“…As shown in Scheme 2 , the furylruthenium complex 4c was also prepared via deprotonation of the vinylidene complex 2c containing a ethyl acetate at Cγ. Similar reaction has been reported [ 52 ]. Deprotonation reaction of dinuclear vinylideneruthenium complexes containing an ester substituent at Cγ gave the dinuclear bisfuryl complexes [ 49 ].…”

“…The synthesis of a number of ruthenium cyclopropenyl complexes by deprotonation of readily accessible ruthenium vinylidene complexes containing a CH 2 R group bound to Cβ has been reported [ 49 , 50 , 51 , 52 , 53 ]. A cyclopropenylruthenium complex containing pentamethylcyclopentadiethyl (Cp*) and dppp ligands was synthesized as well [ 50 ].…”

“…The X-ray diffraction analysis of the furylruthenium complex containing Cp and two PPh 3 ligands has been reported [ 52 ]. The Ru-Cα bond length in the furylruthenium complex of 2.076(7) Å indicates a single bond.…”

Grubb’s and Wilkinson catalyzed reactions of 2-phenyl-3-vinyl substituted 2H-azirines

“…16 By comparison with the extensive photochemical and thermal studies of the 2H-azirine ring system, its behavior toward organometallic reagents has been relatively unexplored. In some earlier work, Alper and Wollowitz 17 demonstrated that group VI metal carbonyls.…”

Reactions of a Ruthenium Complex with Substituted N‐Propargyl Pyrroles

“…Deprotonation of 10 a by nBu 4 NOH inducedt he cyclization reaction to yield the neutralf uryl complex 12 a in 10 min, as shown in Scheme 4. [21] Similarly,d eprotonation of 11 a by nBu 4 NOH yields the NMRobservable neutralf uryl complex 13 a,w hich is unstablea nd readily converts into 14 a quantitativelyt hrough 1,3-benzyl migration. In the 1 HNMR spectrumo f14 a,t he doublet resonance at d = 9.63 ppm is assigned to the aldehyde group, with al ong-range coupling with the pyrrolic hydrogen.…”