248764-48-9Relevant academic research and scientific papers
Reactions of imines with half-open titanocenes: Substituent effects and tandem couplings with nitriles and isonitriles
Tomaszewski, Robert,Lam, Kin-Chung,Rheingold, Arnold L.,Ernst, Richard D.
, p. 4174 - 4182 (2008/10/08)
The syntheses and characterizations of half-open titanocenes containing bulky Cp ligands are described. Such species include Ti[1,3-C5H3(t-C4H9) 2](Pdl)(PX3) (Pdl = 2,4-C7H11, X = Me; Pdl = C5H7, X = Me or Et) and Ti[1,3-C5H3(SiMe3)2](2,4-C 7H11)(PMe3) (C7H11 = dimethylpentadienyl). The structure of Ti[1,3-C5H3(t-C4H9) 2](C5H7)PMe3 was determined, and revealed markedly shorter Ti-C bonds for the open dienyl ligand as compared to the cyclic one. The first 2,4-C7H11 complex undergoes a coupling reaction with imines, generating a chiral center with the opposite stereochemistry, as demonstrated by a solid-state structural determination, as occurs in a similar coupling reaction with the Ti(C5H5)(2,4-C7H11) fragment. In addition, mixed coupling reactions can be achieved through the addition of nitriles or isonitriles to the C6H5C(H)=N(i-C3H7)-Ti(C 5H5)(2,4-C7H11) coupling product. These reactions result in the incorporation of either one equivalent of nitrile (p-CH3C6H4CN) or four equivalents of isonitrile (P-CH3C6H4NC). Structures of both of these species were determined, and a mechanism is proposed for the latter reaction.
