Institute of Organic Chemistry, Polish Academy of Sciences, Warsaw, Poland

Ruthenium carbene complexes (1a–c) are the most used catalysts for olefin metathesis. Their popularity is due to the fact that usually high reactivity can be achieved by using mild reaction conditions. Also the remarkable property of being tolerant towards a lot of organic functional groups has been a determining factor in the success-story of these catalysts.¹

Although the reactivity of catalysts 1a–c and 2 towards some substrates is well documented, this area is far from being fully explored. Recently, we have developed the Hoveyda-type ruthenium complex 3, possessing a dramatically enhanced reactivity, e.g., 3 promotes metathesis even at 0°C.² Preparation of ruthenium complexes 3–4 and their applications in metathesis of several „problematic“ substrates, such as a,b-unsaturated nitriles,^2a sulphones,³ vinyl phosphine oxides⁴ etc. will be presented. The observed substitution effects will be discussed.

1. Trnka, T. M.; Grubbs, R. H. Acc. Chem. Res. 2001, 34, 18–29.

2. [2a]Grela, K.; Harutyunyan, S.; Michrowska, A. Angew. Chem., Int. Ed. 2002, 41, 4038–4040 (Angew. Chem. 2002, 114, 4210–4212). For applications of 3, see: [2b] Honda, T.; Namiki, H.; Kaneda, K.; Mizutani, H. Org. Lett. in print. [2c] Ostrowski, S.; Mikus, A. Mol. Divers. in print.

3. Grela, K.; Michrowska, A.; Bieniek, M.; Kim, M.; Klajn, R. Tetrahedron 2003, 59, 4525–4531.

4. Demchuk, O. M.; Pietrusiewicz, K. M.; Michrowska, A.; Grela, K. Org. Lett. 2003, 5, 3217–3220.