| Abstract
| - Reaction of the imidotitanium complexes [(N2Npy-κ3N)Ti(NtBu)(py)] (1) and [(N2Npy-κ3N)Ti(NtBu)] (1a) (N2Npy = (2-C5H4N)C(Me)(CH2NSiMe3)2) with 2-butyne and 1-phenylpropyne led to C−N coupling with the imido ligand and yielded the four-memberedtitanaazetidines [(N2Npy-κ3N)Ti{N(tBu)C(CHCH3)CH2}] (2) and [(N2Npy-κ3N)Ti{N(tBu)C(CHC6H5)CH2}] (3), respectively. The same reaction products were obtained in 2 + 2cycloaddition reactions of 1 and 1a with 1,2-butadiene and phenylallene. The four-memberedmetallacycle with an exocyclic CC double bond was established by X-ray diffraction studiesof both compounds. A mechanism to explain the observed products from both types ofreactions is proposed. Whereas the reactions of 1 with CO2, tBuNCO, and PhNCO werehighly unspecific and did not lead to an isolable product, the conversion with the stericallyencumbered isocyanate 2,6-iPr2C6H3NCO yielded the product of 2 + 2 cycloaddition to theTiN bond, namely [(N2Npy-κ3N)Ti{N(tBu)C(N-2,6-C6H3iPr2)O}(py)] (4), the structure ofwhich was elucidated by NMR spectroscopy.
- Reaction of the imidotitanium complex [(N2Npy-κ3N)Ti(NtBu)(py)] (A; N2Npy = (2-C5H4N)C(Me)(CH2NSiMe3)2) or its pyridine adduct with 2-butyne and 1-phenylprophne led to C−N coupling with the imido ligand and yielded the four-membered titanaazetidines [(N2Npy-κ3N)Ti{N(tBu)C(CHR)CH2}] (B; R = CH3, Ph), while the sterically encumbered isocyanate 2,6-iPr2C6H3NCO yielded the product of 2 + 2 cycloaddition to the TiN bond.
|
