[reaction: see text]. The carbohydrate-derived chiral monophosphites with additional groups have been synthesized and used for asymmetric hydrogenation of dimethyl itaconate and enamides. Up to 99.6% ee and 98.5% ee have been obtained, respectively.

We report on a new class of P-O monophosphite ligands (designated 3a-k) with a double six-membered-ring backbone onto which are attached additional groups and on applications of their Rh complexes in the hydrogenation of enamides, alpha-dehydroamino acid esters, dimethyl itaconate, and beta-(acylamino)acrylates. Our results demonstrate that the Rh complexes with ligands 3a-k exhibit high enantioselectivity and reactivity in asymmetric hydrogenation reactions. An ee value of up to 98.0% was obtained for the hydrogenation of alpha-dehydroamino acid esters, and the ee values were all over 99% for the other three types of substrate, with a turnover number of up to 5000.

Enantioselective synthesesEnantioselective syntheses O 0031 Chiral Monophosphites Derived from Carbohydrate: Conformational Effect in Catalytic Asymmetric Hydrogenation. -Several monophosphite ligands bearing additional groups derived from D-fructose and D-glucose are synthesized (16 examples) and employed as ligands in the rhodium-catalyzed hydrogenation of itaconate (III) and enamides (V) and (VII). Excellent enantioselectivities are achieved indicating that the ketalated carbohydrate groups in the phosphites have beneficial effects in asymmetric catalysis. -(HUANG, H.; ZHENG*, Z.; LUO, H.; BAI, C.; HU, X.; CHEN*, H.; Org.