Stereocontrol in the synthesis of cyclic amino acids: a new ligand for directed hydrogenation through hydrogen bonding.

A system for the directed hydrogenation of nitrogen heterocycles is described in which hydrogen is delivered cis to a hydroxymethyl group by a rhodium catalyst with a simple phosphine ligand. The chemistry is applied to the synthesis of the hygric acid moiety of lincomycin and the pipecolic acid moiety of Argatroban. A series of control experiments indicate that the stereoselectivity is a result of a combination of both coordination and hydrogen bonding.

Palladium-Catalyzed Asymmetric Arylation of Trifluoromethylated/Perfluoroalkylated 2-Quinazolinones with High Enantioselectivity.

Asymmetric arylation of 4-fluoroalkyl-2-quinazolinone derivatives with arylboronic acids proceeded smoothly in the presence of a cationic palladium catalyst (1 mol %) coordinated with a chiral phosphinooxazoline (phox) ligand to create the corresponding fluorine-containing arylated dihydroquinazolinones in high yields and with greater than 99 % ee.

Phosphine-catalyzed regioselective Michael addition to allenoates.

The first phosphine catalysed Michael addition of arylcyanoacetates to allenoates has been developed, and the ß-selective products with a quaternary center were obtained in excellent yields. This unusual regioselectivity may open new opportunities to access interesting molecular structures.