A chemoenzymatic access to D- and L-sphingosines employing hydroxynitrile lyases

A chemoenzymatic access to D- or L-sphingosines is presented comprising of a total synthesis of the L-threo-isomer and formal. syntheses of the other three isomers. Key to the development of a general synthetic strategy has been the use of enantiocomplementary hydroxynitrile lyases (Hnls) to yield an enantiomeric pair of starting materials. The (S)-Hnl from Hevea brasiliensis has been used to prepare L-threo-sphingosine in 14 steps and an overall 12% yield. Application of the (R)-Hnl from Prunus amygdalus formally allows synthesis of D-threo- and D-erythro-sphingosines. (C) 2000 Elsevier Science Ltd. All rights reserved.