The synthesis of an optically pure proline-based tryptophan mimetic is described. The strategy involves the in situ generation of an unprecedented allylmetal species containing the indole moiety, and its coupling with a chiral imine. The construction of the 3-substitued proline skeleton is then achieved through a hydrozirconation/iodination sequence applied to the resulting homoallylic amine.
Cyclopent-2-enylaluminium as allylzinc precursor for the diastereoselective allylmetallation of non-racemic imines: applications to the synthesis of enantiomerically enriched heterocycles
A sequential titanium-catalyzed/hydroalumination/transmetallation/allylation of non-racemic imines which provides tunable homoallylamines for heterocyclic synthesis is presented.