Synthesis of new chiral phosphorous- and nitrogen-containing ligands from resin acids.

Starting from the phytogenic diterpenes, chiral phosphine, urea, and thiourea derivatives were synthesized. Using these new chiral ligands, Rh(I) and Ru(II) complexes were prepared and used as catalysts for the catalytic asymmetric hydrogenation of unsaturated carboxylic acids and asymmetric hydrogen-transfer reduction of carbonyl compounds. Although the enantiopurity of the products obtained was not high, it was demonstrated that chiral ligands derived from diterpenes could be used for asymmetric reduction.