PALLADIUM-CATALYZED INTERMOLECULAR ARYLATION OF FUNCTIONALLY-SUBSTITUTED CYCLOALKENES BY ARYL IODIDES

The palladium-catalyzed, intermolecular arylation of functionally-substituted cycloalkenes by aryl iodides affords a new synthetic route to a variety of arylated cyclic derivatives. The arylation of 2-cyclopenten-1-ol and 2-cyclo-hexen-1-ol provides modest yields of the corresponding 3-arylcycloalkanones, while 2-methyl-2-cyclopenten-1-ol affords a mixture of singly and doubly arylated cyclopentanone products. 1-Acetoxycyclopentene undergoes arylation to produce the corresponding allylic aryl substitution product opening up a new route far the alpha-arylation of cycloalkanones. Cyclic allylic ethers undergo arylation at both ends of the C-C double bond to generate mixtures of singly arylated vinylic ethers. 1-Cyanocyclopentene reacts with aryl iodides under palladium catalysis to produce 1-cyano-5-arylcyclopentenes in high yield. 2-Methyl-2-cycloalken-1-ones afford modest yields of doubly arylated 2-cycloalken-1-ones in a single step.