Metal Stille cross-coupling reaction

For reviews see (a) Mitchell TN. In Diedrich F, Stang PG, eds. Metal Catalysed Cross-Coupling Reactions. Weinheim Verlag GmbH, Wiley VCH, 1988 197-202 (b) Farina V, Krishnamurthy V, Scott WJ. In Paquette LA, ed. The Stille Reaction. Organic Reactions 1997, Vol. 50. New York John Wiley Sons, Inc., 1997 1-676. 

The Stille reaction in its traditional form is thus now well established, and finds many uses in preparative chemistry. The use of other transition metals in cross-coupling reactions involving organotins is still in its infancy, however, and it seems very worthwhile to investigate this aspect of tin chemistry further, as it is likely to provide other useful weapons for the armory of that insatiable beast, the synthetic organic chemist. 

Reviews (a) Farina, V., Krishnamurthy, V., Scott, W.J. The Stille Reaction Wiley, New York, 1999. (b) Mitchell, T. N. in Metal-Catalyzed Cross-Coupling Reactions Diederich, F., Stang, P.J., Eds. Wiley-VCH, Weinheim, Germany, 1998, Chapter 4. (c) Tsuji, J. Palladium Reagents and catalysts John Wiley Sons, Chichester, 1995. (d) Stan-forth, S.P. Tetrahedron 1993, 54, 263. (e) Farina, V., Krishnamurthy, V., Scott,... 

For example de Meijere A, Diederich F (eds) (2004) Metal-catalyzed cross-coupling reactions, second completely revised and enlarged editirai, vol 2. Wiley-VCH, Weinheim, 437 pp Oestreich M (2009) The Mizoroki-Heck reactioiL Wiley, Hoboktai, NJ, 938 pp Farina V, Scott WJ (1998) The Stille reactirm. Wiley, New York, NY, 672 pp Li JJ, (jribble GW (2006) Palladium in heterocyclic chtanistry, 2nd edn. Pergamon/Elsevier, Oxford... 

Metal-catalyzed cross-coupling reactions have become, in recent years, an important tool in the organic synthetic arsenal. Among the several known cross-coupling reactions that use a quinoline fragment as a coupling partner, Suzuki and Stille are more widespread. On the other hand, only a few precedents exist for Negishi and Hiyama reactions. 

The reaction between an organic electrophile 1 and an organostannane 2 mediated by a transition metal catalyst (originally palladium) to form a new sigma carbon carbon bond is referred to as the Stille cross-coupling reaction (equation 1). 

The application of modem solid-phase chemistry to metal catalyzed cross coupling reaction (including the Stille coupling) has been the subject of a very recent review by Testero and Matta. Ionic liquid supported tin reagents have also been developed." ... 

AT-acetyltryptamines could be obtained via microwave-assisted transition-metal-catalyzed reactions on resin bound 3-[2-(acetylamino)ethyl]-2-iodo-lH-indole-5-carboxamide. While acceptable reaction conditions for the application of microwave irradiation have been identified for Stille heteroaryla-tion reactions, the related Suzuki protocol on the same substrate gave poor results, since at a constant power of 60 W, no full conversion (50-60%) of resin-bound 3-[2-(acetylamino)ethyl]-2-iodo-lH-indole-5-carboxamide could be obtained even when two consecutive cross-coupling reaction cycles (involving complete removal of reagents and by-products by washing off the resin) were used (Scheme 36). Also under conventional heating at 110 °C, and otherwise identical conditions, the Suzuki reactions proved to be difficult since two cross-coupling reaction cycles of 24 h had to be used to achieve full conversion. 

Transition metal-catalysed reactions have emerged as powerful tools for carbon-carbon (C-C) bond formation [1], Cross-coupling reactions (Suzuki-Miyaura, Mizoroki-Heck, Stille, etc.) are recognised to be extremely reliable, robust and versatile. However, some other catalysed arylation reactions have been studied and have been reported to be very efficient [2]. In recent years, A -heterocyclic carbenes (NHC) have been extensively studied and their use as ligands for transition-metal catalysis has allowed for the significant improvement of many reactions [3]. This chapter highlights the use of NHC-bearing complexes in those arylation reactions. 

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