Coupling reactions tris dipalladium

Reductive coupling of two organic ligands from a pair of metal complexes has already been reviewed [94], More recently, kinetic studies on reductive elimination from di- and tri-nuclear metal complexes have been reported [95,96], For C-H reductive elimination reactions from dipalladium complexes with the A-frame structure [Pd2R2(At-H)( -dppm)2]+, a concerted mechanism involving a W-shaped intermediate has been proposed (Scheme 9.38) [95a],... 

For additional discussion about palladium-catalyzed coupling reactions, see also those entries dealing with organopalladium catalysis (e.g. tetrakis(triphenylphosphine)palladium(0), tris-(dibenzylideneacetone)dipalladium-chloroform, and ( )-l-tri-methylsilyl-2-trimethylstannylethylene. 

A bromo or iodo substituent is not always necessary in order to generate the organo-lithium and a number of directed metalla-tion procedures are useful [118, 119]. Several examples of alternative catalysts for use in coupling reactions have also been reported, such as palladium acetate [22], tris(di-benzylideneacetone)dipalladium [117] and... 

Porco s pathway to complete the synthesis of (- )-kinamycin C (3) is shown in Scheme 3.8. The arylstannane 34 and the a-bromoenone 35 were efficiently coupled by a Stille reaction using tris(dibenzylideneacetone)dipalladium and triphenylarsine... 

Palladium can also catalyze cross-coupling between aryl halides and aryl or vinylstannanes and there are examples of application of this reaction in the synthesis of pyrroles and indoles. 1-Tosyl-3-(tri-n-butylstannyl)indole gives good yields of coupling products with vinyl and aryl iodides and triflates. The recommended catalyst is tris-(dibenzylideneacetone)-dipalladium (5 mol%) used with triphenylarsine (10 mol%) (Equation (121)) <94TL2405>. 

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