3 years ago

From Five to Five: Titanium Ketimine Complexes with Monoaza-butadiene η4-Coordination Mode and Hidden η2-Imine Reactivity

From Five to Five: Titanium Ketimine Complexes with Monoaza-butadiene η4-Coordination Mode and Hidden η2-Imine Reactivity
Marc Schmidtmann, Rüdiger Beckhaus, Malte Fischer
In the reactions of LTiCl3 (L: Cp*, Cp), Mg, and PhN═C(p-tolyl)2 (1) the formation of η4-ketimine complexes Cp*Ti(Cl)(η4-PhN═C(p-tolyl)2) (2a) and CpTi(Cl)(η4-PhN═C(p-tolyl)2) (2b) are observed. Their “nonclassic” five-membered titanium monoazabutadiene envelope coordination modes, involving one of the p-tolyl substituents, is confirmed by single crystal X-ray diffraction analysis of 2b. In reactions of 2 with aldehydes, ketones, alkynes, carbodiimides, isocyanates, isothiocyanates, and imines five-membered titanacycles are formed in a regioselective manner. This behavior is in agreement with a hidden η2-imine reactivity. All reaction products are fully characterized, including single crystal X-ray diffraction studies. For the PhC≡CH insertion products (4b, 4c) the formation of Ti–C(Ph) units are observed. By insertion of the isocyanate CyNCO the formation of a Ti–N bond in 6a is preferred in comparison to the insertion of the isothiocyanate PhNCS, where a Ti–S bond is formed (7a). By reacting 2a with aldimine PhN═C(H)(p-tolyl) the nonsymmetric titanaimidazolidine derivative 8a is formed by subsequent ketimine–aldimine coupling. By derivatization of 2a with LiN(Me)Cy the formation of a the titanadihydropyrrole 9a is observed, caused by a 1,3-H-shift. 2 appears to be inert toward a broad range of terminal olefins. Reacting 2a with allyl ethyl ether results in a spontaneous ether cleavage reaction to 10a.

Publisher URL: http://dx.doi.org/10.1021/acs.organomet.7b00673

DOI: 10.1021/acs.organomet.7b00673

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.