Interaction of PdCl₂-2-(β-diphenylphosphine)ethylpyridine Complex with Diols and CO: Synthesis of New Alkoxycarbonyl Complexes, Key Intermediates to Cyclic Carbonates

Abstract

PdCl2PN (PN ) 2-(â-diphenylphosphine)ethylpyridine) was found to be effective in the promotion of
\nthe alkoxycarbonylation of diols [(1,2-hydroxyethane (HE); 1,2- and 1,3-hydroxypropane (1,2HP, 1,3HP),
\n1,2-, 1,3-, and 1,4-hydroxybutane (1,2HB, 1,3HB, 1,4HB)]. The relevant mono-alkoxycarbonyl complexes
\nof the diols, of formula PdClPN(COO-R-OH), were isolated, characterized in solution, and studied for
\ntheir reactivity. All complexes in the presence of different reagents release the alkoxycarbonyl group
\ndirectly as cyclic carbonate or as chloroformate, which “in situ” converts into cyclic carbonate or other
\nvaluable carbonyl products. The structure of the complexes PdCl[(COO-CH2-CH2-CH2(OH)](PN) (4c)
\nand PdCl(COO-CH2-CH(OH)-C2H5)(PN) (4d) was also derived by single-crystal X-ray diffraction.