Palladium acetate—Triphenylarsine

Heck reaction of 5-iodo-2,4-dimethoxypyrimidine and the furanose 3-deoxyglycal 147 with catalytic quantities of palladium acetate gives a mixture of the 2,3- and 3,4-enes 148 and 149 (Scheme 15). With triphenylarsine also present the latter product is favored, whereas with triphenylphosphine the 2-ene is produced without its isomer.164 Further examples of this type of chemistry have been reviewed by Daves.118... 

Alkenylations can also be carried out the optimum conditions for 2-bromopropene with palladium acetate include the use of triphenylarsine with silver carbonate and triethylamine, but the advantages over more amenable conditions, using triphenylphosphine with potassium or cesium carbonate, are marginal. ... 

Palladium-catalyzed hydroarylation of sterically hindered PTAD adduct 157 with aryl halides in the presence of triphenylarsine, sodium acetate, and DMSO provides a 1 1 mixture of 170 and 171. The same reaction done with sodium fluoride and formic acid provides mixtures containing 171 as the major product. Apparently, the use of sodium fluoride as a base allows the selective formation of the opening products 171 in good yields (Equation 19). Similarly, the 2,3-phthalazine-l,4-dione adduct 172 provides the corresponding products 173 and 174 (Equation 20) <2002AGE3375>. 

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