CYCLOADDITION OF IMINES AND BUTN=O WITH THE CARBYNE COMPLEXES [CP(CO)2MN=CTOL]+, [CP(CO)2RE=CTOL]+

The cationic carbyne complex [Cp(CO)2Re≡CTol]+ (2) reacts with the imines PhCH═NCH3 and PhCH═N—N═CHPh to give a net [2 + 2] cycloaddition of the imine across the metal-carbyne linkage and form the metallacycles [Cp(CO)2Re(η2(C,C)-C{Tol}N{R}CH{Ph})]+ (3, R = CH3; 4, R = N═CHPh). Complex 3 is hydrolytically unstable and reacts with water to form benzaldehyde and the carbene complex Cp(CO)2Re═C(NHMe)Tol. Trimethylphosphine adds to the tolyl-substituted carbon of complex 3 to form the new metallacycle [Cp(CO)2Re(η2(C,C)-CH{Ph}N{Me}C{Tol}{PMe3}]+. Upon photolysis, the BCl4- salt of complex 3 loses CO and abstracts Cl- from the BCl4- anion to form Cp(CO)ClRe(η2(C,C)-C{Tol}N-{Me}CH{Ph}). A similar chloride abstraction occurs when the BCl4- salt of [Cp(CO)2Re≡CTol]+ reacts with ButN═O to give Cp(CO)(Cl)Re{η2(C,O)-C(O)C(Tol)N(But)O}, 15, in which a CO ligand has also inserted between the Re atom and the carbyne carbon. In contrast, the BPh4- salt of [Cp(CO)2Re≡CTol]+ reacts with ButN═O by a net [2 + 2] cycloaddition reaction to form [Cp(CO)2Re{η2(C,O)-C(Tol)N(But)O)]BPh4, 16. The metallacycle 15 can be converted into 16 by abstraction of chloride with Ag+, and complex 16 reacts with excess PMe3 to form (CO)2(PMe3)2Re{η2(C,O)-C(Tol)N(But)O}, 18, in which the metallacycle has been retained but the Cp ligand has been displaced. Reaction of the BCl4- salt of [Cp(CO)2Re≡CTol]+ with the dimer [ButN═O]2 leads to the formation of the five-membered metallacycle [Cp(CO)2Re(η2-(C,O)-C(O)C(Tol)N(But)O}]BCl4. In contrast to the reactions of 2, the manganese carbyne complex [Cp(CO)2Mn≡CPh]+ reacts with PhCH═NCH3 and PhCH═N—N═CHPh to give new carbene complexes which result from insertion of the imine between the carbyne carbon and a carbon atom of the Cp ligand. The complex [Cp*(CO)2Mn≡CTol]BCl4 (12) reacts with PhCH═NCH3 to give an analogous product formed by an unprecedented substitution of a Cp* methyl group by the imine carbon. Complexes 3, 15, 16, and 18 were crystallographically characterized: 3, triclinic, P1, a = 10.367 (2), b = 11.306 (2), c = 11.858 (2) Å, α = 83.96 (2), β = 83.04 (2), γ = 67.78 (2)°, V = 1274.6 (5) Å3, Z = 2, R(F) = 3.56%, R(wF) = 4.53% for 4804 reflections with Fo > 5σ(Fo); 15, orthorhombic, Fdd2, a = 21.700 (4), b = 38.016 (7), c = 11.120 (2) Å, V = 9173.4 (22) Å3, Z = 16, R(F) = 5.22%, R(wF) = 5.76% for 4144 reflections with Fo ≥ 5σ(Fo); 16, monoclinic, P21/c, a = 9.007 (2), b = 15.003 (4), c = 27.839 (6) Å, β = 95.67 (2)°, V = 3743 (2) Å3, Z = 4, R(F) = 4.73%, R(wF) = 4.72% for 5084 reflections with Fo > 5σ(Fo); 18, triclinic, P1, a = 10.026 (2), b = 11.075 (2), c = 11.201 (2) Å, α = 85.76 (2), β = 86.99 (2), γ = 85.59 (2)°, V = 1235.3 (4) Å3, Z = 2, R(F) = 3.88%, R(wF) = 4.21% for 3724 reflections with Fo > 5σ(Fo). © 1990, American Chemical Society. All rights reserved.