A library of low-coordinate titanium and vanadium complexes containing terminal metal-ligand multiply bonded functionalities such as alkylidenes,1-4 alkylidynes,5 and imides6 have been prepared in our group by one-electron oxidatively-induced α-hydrogen abstraction reactions (Scheme 1). In the case of the alkylidene motif, the nucleophilic nature of the M-C multiple bond permits subsequent reactions such as α-hydrogen migration to generate other unprecedented functionalities such as phosphinidene alkyl7,8 and imide alkyls3 (Scheme 2). The entry into d 0-metal alkylidenes is often restricted to α-H abstraction reactions where a good leaving group is generated (e.g., an alkane or a very weak conjugate acid), and access to low-coordinate systems possessing this functionality can be difficult or limited since formation of the metal-alkylidene bonds typically stem from a high-oxidation-state and coordinatively saturated complex. For this reason, an attractive approach to the assembly of low-coordinate systems possessing metal-ligand multiple bonds can be derive from a redox reaction where the low-valent metal is alkylated, then oxidized. Another advantage of generating metal-ligand multiple bonds via “oxidatively-induced α-hydrogen abstraction reactions,” is the ability to perform substitution chemistry with the halide or pseudohalide complexes bearing the terminal alkylidene, alkylidyne, or imide functionality. As a result, a cascade of reactivity can be derived from a simple one-electron oxidation step!
Selected References
1. Basuli, F.; Bailey, B. C.; Tomaszewski, J.; Huffman, J. C.; Mindiola, D. J. J. Am. Chem. Soc. 2003, 125, 6052-6052.
2. Basuli, F.; Bailey, B. C.; Watson, L. A.; Tomaszewski, J.; Huffman, J. C.; Mindiola, D. J. Organometallics 2005, 24, 1886-1906.
3. Bailey, B. C.; Huffman, J. C.; Mindiola, D. J.; Weng, W.; Ozerov, O. V. Organometallics 2005, 24, 1390-1393.
4. Basuli, F.; Kilgore, U. J.; Hu, X.; Meyer, K.; Pink, M.; Huffman, J. C.; Mindiola, D. J. Angew. Chem. Int. Ed. 2004, 43, 3156-3158.
5. Basuli, F.; Bailey, B. C.; Brown, D.; Tomaszewski, J.; Huffman, J. C.; Baik, M.-H.; Mindiola, D. J. J. Am. Chem. Soc. 2004, 126, 10506-10507.
6. Basuli, F.; Bailey, B. C.; Huffman, J. C.; Mindiola, D. J. Chem. Commun. 2003, 1554-1555.
7. Basuli, F.; Tomaszewski, J.; Huffman, J. C.; Mindiola, D. J. J. Am. Chem. Soc. 2003, 125, 10170-10171.
8. Basuli, F.; Bailey, B. C.; Huffman, J. C.; Baik, M.-H.; Mindiola, D. J. J. Am. Chem. Soc. 2004, 126, 1924-1925.
