Diastereoselective Pictet–Spengler reactions of L -(Boc)phenylalaninal and L -(Boc)prolinal: biomimetic syntheses of eudistomin T and (–)-woodinine

The diastereoselective Pictet–Spengler reaction of L-(Boc)phenylalaninal with tryptamine and the elaboration of this intermediate to the antibacterial compound eudistomin T and analogues of the antileukaemic compound eudistomidin B are described. We also report an efficient synthesis of the naturally occurring alkaloid (–)-woodinine from L-(Boc)prolinal and 5-bromotryptamine in three steps, using a diastereoselective Pictet–Spengler reaction. This approach affords, in addition, formal syntheses of the marine alkaloids eudistomins H and I.