Tethered Bis(amidate) and Bis(ureate) Supported Zirconium Precatalysts for the Intramolecular Hydroamination of Aminoalkenes

Tethered bis(amide) and bis(urea) proligands featuring a neutral chalcogen donor (O or S) in the backbone were synthesized and installed on zirconium via protonolysis. The bis(amidate) zirconium complexes adopt a κ4(N,N,O,O) binding motif and were characterized in the solid state with a pyridine donor. Likewise, the bis(ureate)-supported complexes are also found to have a κ4(N,N,O,O) binding motif in the solid state however no additional donor ligand is required for discrete complex formation. No evidence for interaction between the neutral chalcogen donor and the zirconium atom is found for any of the transition metal species. All complexes were screened as precatalysts for the intramolecular hydroamination reaction with both primary and secondary aminoalkene substrates. Interestingly, the bis(ureate) species show similar reactivity to the bis(amidate) species, in contrast to a recently reported alkyl-bridged bis(ureate) complex, which readily cyclizes secondary aminoalkenes.

[1]  S. Tobisch.  Intramolecular aminoalkene hydroamination mediated by a tethered bis(ureate)zirconium complex: computational perusal of various pathways for aminoalkene activation. , 2012, Inorganic chemistry.

[2]  Jie Xiao,et al.  Synthesis, Structure, and Reactivity Study of Iron(II) Complexes with Bulky Bis(anilido)thioether Ligation , 2012 .

[3]  L. Schafer,et al.  Mechanistic elucidation of intramolecular aminoalkene hydroamination catalyzed by a tethered bis(ureate) complex: evidence for proton-assisted C-N bond formation at zirconium. , 2011, Journal of the American Chemical Society.

[4]  L. Schafer,et al.  Tetrakis(dimethylamido)zirconium(IV) , 2011 .

[5]  L. Schafer,et al.  Broadening the scope of group 4 hydroamination catalysis using a tethered ureate ligand. , 2009, Journal of the American Chemical Society.

[6]  L. Schafer,et al.  N,O‐Chelates of Group 4 Metals: Contrasting the Use of Amidates and Ureates in the Synthesis of Metal Dichlorides , 2009 .

[7]  T. Müller,et al.  Hydroamination: direct addition of amines to alkenes and alkynes. , 2008, Chemical reviews.

[8]  Carsten Müller,et al.  Neutral Group-IV Metal Catalysts for the Intramolecular Hydroamination of Alkenes , 2008 .

[9]  S. Majumder,et al.  Group-4 Dipyrrolylmethane Complexes in Intramolecular Olefin Hydroamination , 2008 .

[10]  T. Marks,et al.  Mechanistic investigation of intramolecular aminoalkene and aminoalkyne hydroamination/cyclization catalyzed by highly electrophilic, tetravalent constrained geometry 4d and 5f complexes. Evidence for an M-N sigma-bonded insertive pathway. , 2007, Journal of the American Chemical Society.

[11]  J. Kozak,et al.  Chiral neutral zirconium amidate complexes for the asymmetric hydroamination of alkenes. , 2006, Angewandte Chemie.

[12]  A. Danopoulos,et al.  Dimethylxanthene- and dibenzofuran-diamido complexes of titanium , 2006 .

[13]  K. Hultzsch,et al.  Hydroamination/cyclization of aminoalkenes using cationic zirconocene and titanocene catalysts. , 2004, Angewandte Chemie.

[14]  P. Scott,et al.  Zirconium catalysed enantioselective hydroamination/cyclisation. , 2004, Chemical communications.

[15]  L. Schafer,et al.  Amidate complexes of titanium and zirconium: a new class of tunable precatalysts for the hydroamination of alkynes. , 2003, Chemical communications.

[16]  Yoshiaki Yamada,et al.  Ruthenium Complexes Containing Bis(diarylamido)/Thioether Ligands: Synthesis and Their Catalysis for the Hydrogenation of Benzonitrile , 2002 .

[17]  W. M. Davis,et al.  Synthesis of Titanium, Zirconium, and Hafnium Complexes That Contain the [(MesitylN-o-C6H4)2O]2-Ligand , 2000 .

[18]  W. M. Davis,et al.  Synthesis of Group 4 [(RN-o-C6H4)2O]2− complexes where R is SiMe3 or 0.5 Me2SiCH2CH2SiMe2 , 1999 .

[19]  W. M. Davis,et al.  Synthesis of Titanium, Zirconium, and Hafnium Complexes that Contain Diamido Donor Ligands of the Type [(t-BuN-o-C6H4)2O]2- and an Evaluation of Activated Versions for the Polymerization of 1-Hexene , 1999 .

[20]  W. M. Davis,et al.  Titanium and Zirconium Complexes That Contain the Tridentate Diamido Ligands [(i-PrN-o-C6H4)2O]2- ([i-PrNON]2-) and [(C6H11N-o-C6H4)2O]2- ([CyNON]2-) , 1999 .

[21]  W. M. Davis,et al.  Synthesis of Zirconium Complexes Containing the Tridentate Diamido Ligands [(t-Bu-d6-N-o-C6H4)2S]2- and [(i-PrN-o-C6H4)2S]2- , 1999 .

[22]  W. M. Davis,et al.  Synthesis of yttrium complexes that contain the [NON]{sup 2-} ligand, [(t-Bu-d{sub 6}-N-o-C{sub 6}H{sub 4}){sub 2}O]{sup 2-} , 1998 .

[23]  W. M. Davis,et al.  Synthesis of Titanium and Zirconium Complexes That Contain the Tridentate Diamido Ligand, [((t-Bu-d6)N-o-C6H4)2O]2- ([NON]2-) and the Living Polymerization of 1-Hexene by Activated [NON]ZrMe2 , 1997 .

[24]  David J. Williams,et al.  SYNTHESES OF LIGANDS CONTAINING TWO AND THREE 2,2'-(BISAMINO)DIPHENYL ETHER UNITS DESIGNED FOR MOLECULAR SELF-ASSEMBLY ON LITHIATION , 1996 .

[25]  Barry M. Trost,et al.  Atom Economy—A Challenge for Organic Synthesis: Homogeneous Catalysis Leads the Way , 1995 .

[26]  T. Livinghouse,et al.  Intramolecular [2+2] cycloadditions of group IV metal-imido complexes. Applications to the synthesis of dihydropyrrole and tetrahydropyridine derivatives , 1992 .

[27]  J. Wilshire.  The Reduction of Some 2,2'-Dinitrodiaryl Compounds and Related Compounds by Thiourea S,S-Dioxide (Formamidinesulfinic Acid) , 1988 .