3 Transition metals in organic synthesis Part (i) Catalytic applications

Abstract

Important investigations in many key areas have been reported upon in 2002. Transition metal catalysed reactions continue to grow in stature, with outstanding selectivity and high yields observed in both old and new synthetic transformations. In particular, a number of efficient ruthenium catalysts have been developed for the cross-metathesis of alkenes, making this a very useful synthetic transformation. Efficient palladium-catalysts for carbon–carbon and carbon–heteroatom bond forming processes continue to be developed, with more catalysts able to transform the less reactive aryl chlorides in a variety of cross-coupling reactions. The versatility of the ruthenium-catalysed cycloisomerisation reactions of 1,n-enynes (n = 6 or 7) is a worthy contribution, which facilitates the synthesis of a range of carbo- and hetero-cycles with excellent regio- and stereo-selectivities. A significant advance in the asymmetric molybdenum-catalysed allylic substitution reaction has been achieved. This reaction is highly regio- and enantio-selective, and for unsymmetrical allylic substrates competes with the palladium-catalysed variant.

The review contains a selection of transition metal catalysed reactions from the chemical literature of 2002. Some reactions also involve a stoichiometric metal component in addition to the transition metal catalyst. The review is divided into reaction type. The review is written in the style of previous years.