Rapid screening of new polymer-supported palladium (II) bis(3,4,5,6-tetrahydropyrimidin-2-ylidenes)

The synthesis of two 1,3-diaryl-3,4,5,6-tetrahydropyrimdin-2-ylidene-based N-heterocyclic carbene-(NHC-) derived palladium complexes, Pd(5-hydroxy-1,3-bis-(2,4,6-trimethylphenyl)-3,4,5,6-tetrahydropyrimidin-2-ylidene)(2)(2+) (Ag2Br2Cl4)(1/2)(4-) (10) and Pd(5-(bicyclo[2.2.1]-hept-5-ene-2-carbonyloxy)-1,3-bis-(2,4,6-trimethylphenyl)-3,4,5,6-tetrahydropyrimidin-2-ylidene)(2)(2+) (Ag2Br2Cl4)(1/2)(4-) (11) is described. 10 was supported on a PS-DVB and a Wang resin, respectively, to yield catalyst 12 and 13, while 11 was used for the synthesis of a ring-opening metathesis precipitation polymerization-derived support 14. All supports were tested for their activity in Heck-type reactions using a combinatorial approach.