Synthesis of 6-endo-hydroxy norphos, a potential ligand for construction of chiral bimetallic catalysts

Synthesis of chiral hydroxyl phospholanes from D-mannitol and their use in asymmetric catalytic reactions

Chiral hydroxyl monophosphane 3 [(2S,3S,4S,5S)-3,4-dihydroxy-2, 5-dimethyl-1-phenylphospholane] and bisphospholanes 5a [1,2-bis[(2S, 3S,4S,5S)-3,4-dihydroxy-2,5-dimethylphospholanyl]benzene] and 5b [1, 2-bis[(2S,3S,4S,5S)-2,5-diethyl-3,4-dihydroxyphospholanyl]benzene] were synthesized from readily available D-mannitol in high yields. Strategies for protection and deprotection of OH-groups in the presence of phosphines have been explored. Rate acceleration in the Baylis-Hillman reaction was observed when a hydroxyl phosphine was used as the catalyst. Rhodium complexes with chiral bisphospholanes are highly enantioselective catalysts for the asymmetric hydrogenation of various kinds of functionalized olefins such as dehydroamino acid derivatives, itaconic acid derivatives, and enamides. An interesting feature of the hydroxyl phospholane system is that hydrogenation of some substrates can be carried out in water with >99% ee and 100% conversion (e.g., itaconic acid).

Rabbit gastric lipase in biocatalytic resolution of 2-hydroxyalkyldiphenylphosphines

Kinetic resolution of 2-hydroxyalkyldiphenylphosphines 4 by acylation with isopropenyl acetate was carried out under rabbit gastric lipase (RGL) catalysis to give optically active 4 and the corresponding acetate, the enantioselectivity factors E ranging from 10 to 20. 1-(2-Naphthyl)ethanol and 2-[N-(ethoxycarbonyl)amino]1-butanol 7 were also resolved.