Reactions of Cyclopentadienyl-Amidinate Titanium Imido Compounds with CS2, COS, Isocyanates, and Other Unsaturated Organic Compounds

New single-, double-, and cross-coupling and imido group transfer reactions of cyclopentadienyl-amidinate titanium imido complexes are described. Reaction of Ti(η-C 5 R 4 Me)(N t Bu)Cl(py) (R = Me or H) with the lithiated benzamidinate Li[PhC(NSiMe 3 ) 2 ] or acetamidinate Li[MeC(N i Pr) 2 ] afforded the tert -butyl imido complexes Ti(η-C 5 R 4 Me)(N t Bu){PhC(NSiMe 3 ) 2 } (R = Me ( 5 ) or H ( 7 )) and Ti(η-C 5 R 4 Me)(N t Bu){MeC(N i Pr 2 ) 2 } (R = Me ( 6 ) or H ( 8 )), respectively. Reaction of 6 with ArNH 2 or TolNH 2 (Ar = 2,6-C 6 H 3 Me 2, Tol = 4-C 6 H 4 Me) afforded the corresponding aryl imido complexes Ti(η-C 5 Me 5 )(NR){MeC(N i Pr 2 ) 2 } (R = Ar ( 9 ) or Tol ( 10 )). Complexes 5, 7, and 8 underwent cycloaddition/extrusion reactions with CS 2 and COS to form μ-sulfido dimers and t BuNCS and t BuNCO, respectively. Compound 6 reacted with COS to form t BuNCO and [Ti(η-C 5 Me 5 )(μ-S){MeC(N i Pr) 2 }] 2, but with CS 2 additional insertion into an amidinate ligand Ti−N i Pr bond occurred to form [Ti(η-C 5 Me 5 )(μ-S){N( i Pr)C(Me)N( i Pr)C(S)S}] 2 . For the aryl imido compounds 9 and 10 the intermediate cycloaddition products Ti(η-C 5 Me 5 ){N(R)C(E)S}{MeC(N i Pr) 2 } (E = S or O) were observed. No further insertion of CS 2 or COS into the Ti−NR bonds occurred. All tert -butyl imido compounds reacted slowly with t BuNCO or ArNCO to form μ-oxo-bridged dimers and t BuNCN t Bu or t BuNCNAr, respectively. Reaction of 9 with t BuNCO gave the N,O-bound ureate Ti(η-C 5 Me 5 ){N(Ar)C(N t Bu)O}{MeC(N i Pr) 2 }, which extruded t BuNCNAr to form [Ti(η-C 5 Me 5 )(μ-O){MeC(N i Pr) 2 }] 2 . Reaction of 9 or 10 with aryl isocyanates gave the N,O-bound ureates Ti(η-C 5 Me 5 ){N(R 1 )C(NR 2 )O}{MeC(N i Pr) 2 } (R 1 = Ar, R 2 = Ar or Tol; R 1 = Tol, R 2 = Ar or Tol ( 25 )), which did not undergo extrusion. Reaction of 25 with TolNCO gave the net cycloaddition−insertion product Ti(η-C 5 Me 5 ){OC(NTol)NTolC(NTol)O}{MeC(N i Pr) 2 }. Several heterocumulene cross-coupling cycloaddition−insertion reactions were studied: for example, the sequential reaction of 10 with TolNCO and CO 2 gave Ti(η-C 5 Me 5 ){OC(O)NTolC(NTol)O}{MeC(N i Pr) 2 }. Aryl imides 9 and 10 reacted with TolNCNTol to form the guanidinate complexes Ti(η-C 5 Me 5 ){N(Tol)C(NTol)N(R)}{MeC(N i Pr) 2 } (R = Ar or Tol). Reaction of 5 and 6 with PhNO gave t BuN NPh and μ-oxo-bridged dimers; the aryl imides 9 and 10 reacted similarly. Ketone and aldehyde C O/Ti NR bond metathesis reactions occurred for certain tert -butyl and aryl imido compounds with MeCOMe, PhCOPh, PhCOH, and PhCOMe, and in some instances intermediates were observed. Slow imide/imine metathesis occurred between Ti(η-C 5 Me 5 )(N-4-C 6 H 4 NMe 2 ){PhC(N i Pr 2 ) 2 } and PhCH(NTol). Compound 6 rapidly converted PhCONH 2 and Me(CH 2 ) 4 CONH 2 to the corresponding nitriles, but the analogous reaction with t BuCONH 2 was slower. Several other titanium imido compounds and Ti(NMe 2 ) 2 Cl 2 were also evaluated for the PhCONH 2 dehydration reaction.