Palladium-catalyzed asymmetric arylation of 2,3-dihydrofuran with phenyl triflate. A novel asymmetric catalysis involving a kinetic resolution process

Article abstract of DOI:10.1021/om00034a064

The reaction of phenyl triflate and 2,3-dihydrofuran in benzene in the presence of a base and a palladium catalyst coordinated with (R)-BINAP gave optically active (R)-2-phenyl-2,3-dihydrofuran (1a) and a small amount of (S)-2-phenyl-2,5-dihydrofuran (2a). The two regioisomers have configurations opposite to each other. A clear correlation was observed between the enantioselectivity and the regioselectivity. Thus, the enantiomeric purity of (R)-1a increases as the ratio of (S)-2a to (R)-1a increases. A catalytic mechanism involving a kinetic resolution process is proposed to account for the relation. Factors controlling the regio- and enantioselectivities are discussed in detail using molecular models based on the X-ray structure of PdCl₂{(R)-BINAP}. Crystal data for PdCl₂{(R)-BINAP}: C₄₄H₃₂Cl₂P₂Pd, a = 11.751(1) ?, c = 26.538(3) ?, V = 3664.2 ?³, tetragonal, P4₁, Z = 4.