Reactions of Cyclopentadienyl-Amidinate Titanium Imido Compounds with CS2, COS, Isocyanates, and Other Unsaturated Organic Compounds
详细信息 查看全文
- 作者：Aldo E. Guiducci ; Catherine L. Boyd ; and Philip Mountford
- 刊名：Organometallics
- 出版年：2006
- 出版时间：February 27, 2006
- 年：2006
- 卷：25
- 期：5
- 页码：1167 - 1187
- 全文大小：464K
- 年卷期：v.25,no.5(February 27, 2006)
- ISSN：1520-6041
文摘
New single-, double-, and cross-coupling and imido group transfer reactions of cyclopentadienyl-amidinate titanium imido complexes are described. Reaction of Ti(
-C5R4Me)(NtBu)Cl(py) (R = Me orH) with the lithiated benzamidinate Li[PhC(NSiMe3)2] or acetamidinate Li[MeC(NiPr)2] afforded thetert-butyl imido complexes Ti(-C5R4Me)(NtBu){PhC(NSiMe3)2} (R = Me (5) or H (7)) and Ti(-C5R4Me)(NtBu){MeC(NiPr2)2} (R = Me (6) or H (8)), respectively. Reaction of 6 with ArNH2 or TolNH2 (Ar= 2,6-C6H3Me2, Tol = 4-C6H4Me) afforded the corresponding aryl imido complexes Ti(-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 
-sulfido dimers and tBuNCS and tBuNCO, respectively.Compound 6 reacted with COS to form tBuNCO and [Ti(-C5Me5)(-S){MeC(NiPr)2}]2, but with CS2additional insertion into an amidinate ligand Ti-NiPr bond occurred to form [Ti(-C5Me5)(-S){N(iPr)C(Me)N(iPr)C(S)S}]2. For the aryl imido compounds 9 and 10 the intermediate cycloaddition productsTi(-C5Me5){N(R)C(E)S}{MeC(NiPr)2} (E = S or O) were observed. No further insertion of CS2 orCOS into the Ti-NR bonds occurred. All tert-butyl imido compounds reacted slowly with tBuNCO orArNCO to form -oxo-bridged dimers and tBuNCNtBu or tBuNCNAr, respectively. Reaction of 9 withtBuNCO gave the N,O-bound ureate Ti(-C5Me5){N(Ar)C(NtBu)O}{MeC(NiPr)2}, which extrudedtBuNCNAr to form [Ti(-C5Me5)(-O){MeC(NiPr)2}]2. Reaction of 9 or 10 with aryl isocyanates gavethe N,O-bound ureates Ti(-C5Me5){N(R1)C(NR2)O}{MeC(NiPr)2} (R1 = Ar, R2 = Ar or Tol; R1 =Tol, R2 = Ar or Tol (25)), which did not undergo extrusion. Reaction of 25 with TolNCO gave the netcycloaddition-insertion product Ti(-C5Me5){OC(NTol)NTolC(NTol)O}{MeC(NiPr)2}. Several heterocumulene cross-coupling cycloaddition-insertion reactions were studied: for example, the sequentialreaction of 10 with TolNCO and CO2 gave Ti(-C5Me5){OC(O)NTolC(NTol)O}{MeC(NiPr)2}. Arylimides 9 and 10 reacted with TolNCNTol to form the guanidinate complexes Ti(-C5Me5){N(Tol)C(NTol)N(R)}{MeC(NiPr)2} (R = Ar or Tol). Reaction of 5 and 6 with PhNO gave tBuN=NPh and-oxo-bridged dimers; the aryl imides 9 and 10 reacted similarly. Ketone and aldehyde C=O/Ti=NRbond 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/iminemetathesis occurred between Ti(-C5Me5)(N-4-C6H4NMe2){PhC(NiPr2)2} and PhCH(NTol). Compound6 rapidly converted PhCONH2 and Me(CH2)4CONH2 to the corresponding nitriles, but the analogousreaction with tBuCONH2 was slower. Several other titanium imido compounds and Ti(NMe2)2Cl2 werealso evaluated for the PhCONH2 dehydration reaction.
-C5R4Me)(NtBu)Cl(py) (R = Me orH) with the lithiated benzamidinate Li[PhC(NSiMe3)2] or acetamidinate Li[MeC(NiPr)2] afforded thetert-butyl imido complexes Ti(-C5R4Me)(NtBu){PhC(NSiMe3)2} (R = Me (5) or H (7)) and Ti(-C5R4Me)(NtBu){MeC(NiPr2)2} (R = Me (6) or H (8)), respectively. Reaction of 6 with ArNH2 or TolNH2 (Ar= 2,6-C6H3Me2, Tol = 4-C6H4Me) afforded the corresponding aryl imido complexes Ti(-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 -sulfido dimers and tBuNCS and tBuNCO, respectively.Compound 6 reacted with COS to form tBuNCO and [Ti(-C5Me5)(-S){MeC(NiPr)2}]2, but with CS2additional insertion into an amidinate ligand Ti-NiPr bond occurred to form [Ti(-C5Me5)(-S){N(iPr)C(Me)N(iPr)C(S)S}]2. For the aryl imido compounds 9 and 10 the intermediate cycloaddition productsTi(-C5Me5){N(R)C(E)S}{MeC(NiPr)2} (E = S or O) were observed. No further insertion of CS2 orCOS into the Ti-NR bonds occurred. All tert-butyl imido compounds reacted slowly with tBuNCO orArNCO to form -oxo-bridged dimers and tBuNCNtBu or tBuNCNAr, respectively. Reaction of 9 withtBuNCO gave the N,O-bound ureate Ti(-C5Me5){N(Ar)C(NtBu)O}{MeC(NiPr)2}, which extrudedtBuNCNAr to form [Ti(-C5Me5)(-O){MeC(NiPr)2}]2. Reaction of 9 or 10 with aryl isocyanates gavethe N,O-bound ureates Ti(-C5Me5){N(R1)C(NR2)O}{MeC(NiPr)2} (R1 = Ar, R2 = Ar or Tol; R1 =Tol, R2 = Ar or Tol (25)), which did not undergo extrusion. Reaction of 25 with TolNCO gave the netcycloaddition-insertion product Ti(-C5Me5){OC(NTol)NTolC(NTol)O}{MeC(NiPr)2}. Several heterocumulene cross-coupling cycloaddition-insertion reactions were studied: for example, the sequentialreaction of 10 with TolNCO and CO2 gave Ti(-C5Me5){OC(O)NTolC(NTol)O}{MeC(NiPr)2}. Arylimides 9 and 10 reacted with TolNCNTol to form the guanidinate complexes Ti(-C5Me5){N(Tol)C(NTol)N(R)}{MeC(NiPr)2} (R = Ar or Tol). Reaction of 5 and 6 with PhNO gave tBuN=NPh and-oxo-bridged dimers; the aryl imides 9 and 10 reacted similarly. Ketone and aldehyde C=O/Ti=NRbond 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/iminemetathesis occurred between Ti(-C5Me5)(N-4-C6H4NMe2){PhC(NiPr2)2} and PhCH(NTol). Compound6 rapidly converted PhCONH2 and Me(CH2)4CONH2 to the corresponding nitriles, but the analogousreaction with tBuCONH2 was slower. Several other titanium imido compounds and Ti(NMe2)2Cl2 werealso evaluated for the PhCONH2 dehydration reaction.