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 cyclopentadienylamidinate titanium imido complexes are described. Reaction of Ti(eta-C5R4Me)(N'Bu)Cl(py) (R = Me or H) with the lithiated benzamidinate Li[PhC(NSiMe3)(2)] or acetamidinate Li[MeC((NPr)-Pr-i)(2)] afforded the tert-butyl imido complexes Ti(eta-C5R4Me)(N'Bu){PhC(NSiMe3)2} (R = Me (5) or H (7)) and Ti(eta-C5R4Me)(N'Bu){MeC(NiPr2)(2)} (R = Me (6) or H (8)), respectively. Reaction of 6 with ArNH2 or TolNH(2) (Ar = 2,6-C6H3Me2, Tol = 4-C6H4Me) afforded the corresponding aryl imido complexes Ti(eta-C5Me5)(NR){MeC(NiPr2)2} (R = Ar (9) or Tol (10)). Complexes 5, 7, and 8 underwent cycloaddition/extrusion reactions with CS2 and COS to form mu-sulfido dimers and (BuNCS)-Bu-t and (BuNCO)-Bu-t, respectively. Compound 6 reacted with COS to form (BuNCO)-Bu-t and [Ti(eta-C5Me5)(mu-S){MeC((NPr)-Pr-i)(2)}](2), but with CS2 additional insertion into an amidinate ligand Ti-(NPr)-Pr-i bond occurred to form [Ti(eta-C5Me5)(u-S){N(Pr-i)C(Me)N(Pr-i)C(S)S}](2). For the aryl imido compounds 9 and 10 the intermediate cycloaddition products Ti(eta-C5Me5){N(R)C(E)S}{MeC((NPr)-Pr-i)(2)} (E = S or O) were observed. No further insertion of CS2 or COS into the Ti-NR bonds occurred. All tert-butyl imido compounds reacted slowly with BuNCO or ArNCO to form mu-oxo-bridged dimers and (BuNCNBu)-Bu-t-Bu-t or (BuNCNAr)-Bu-t, respectively. Reaction of 9 with (BuNCO)-Bu-t gave the N,O-bound ureate Ti(eta-C5Me5){N(Ar)C(N'Bu)O}{MeC((NPr)-Pr-i)(2)}, which extruded (BuNCNAr)-Bu-t to form [Ti(eta-C5Me5)(mu-O){MeC((NPr)-Pr-i)(2)}](2). Reaction of 9 or 10 with aryl isocyanates gave the N,O-bound ureates Ti(eta-C5Me5){N(R-1)C(NR2)O}{MeC((NPr)-Pr-i)(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(eta-C5Me5){OC(NTol)NTolC(NTol)O}{MeC((NPr)-Pr-i)(2)}. Several heterocumulene cross-coupling cycloaddition-insertion reactions were studied: for example, the sequential reaction of 10 with TolNCO and CO2 gave Ti(eta-C5Me5){OC(O)NTolC(NTol)O}{MeC((NPr)-Pr-i)(2)}. Aryl imides 9 and 10 reacted with TolNCNTol to form the guanidinate complexes Ti(eta-C5Me5){N(Tol)C(NTol)N(R)}{MeC((NPr)-Pr-i)(2)} (R = Ar or Tol). Reaction of 5 and 6 with PhNO gave (BuN)-Bu-t=NPh and mu-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(eta-C5Me5)(N-4-C6H4NMe2){PhC((NPr2)-Pr-i)(2)} and PhCH(NTol). Compound 6 rpidly converted PhCONH2 and Me(CH2)(4)CONH2 to the corresponding nitrites, but the analogous reaction with (BuCONH2)-Bu-t was slower. Several other titanium imido compounds and Ti(NMe2)(2)Cl-2 were also evaluated for the PhCONH2 dehydration reaction.