Asymmetric hydrogenation mannitol derivative

The chiral hydroxyphospholanes derived from D-mannitol (MANPHOS) have been used in rhodium-catalyzed asymmetric hydrogenation. Excellent ees were recorded in water as solvent (218). A novel sterically congested tripodal phosphite, TRISPHOS was synthesized and is used for asymmetric hydrosilyla-tion of ketones (219). 

The diphosphine (23), derived from D-mannitol, affords rhodium complexes which are asymmetric, homogeneous hydrogenation catalysts which have been used to produce (S)-amino acids from dehydroamlno acids in 21-58jt optical yields. ... 

Hydrogenation of the ketose derivative (II) produces l-deoxy-l-(aryl-amino) sugar alcohols. Since a new asymmetric center is produced, two isomeric alcohols may be formed, but the yield of the two possible isomers is influenced greatly by the acidity of the medium employed for the hydrogenation (74). In acid solution, catalytic reduction of 1-deoxy-l-p-toluino-fructose (IV) takes place only in the aromatic ring (V) but in alkaline or neutral solution, it takes place with the formation of 1-deoxy-l-p-toluino-mannitol (p-tolyl-D-mannamine) (VI) ... 

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