ABSTRACT
NEt in acetonitrile followed by the treatment with triazol
and a catalytic amount of trifluoroacetic acid. Without isolation of
or any workup, NH
OAc and MeOH are added to allow the formation of the enamine
, which is directly crystallized and isolated in 82% overall yield and 99.6 wt% purity through a simple filtration from the one-pot, three-step reaction mixture. Then,
is converted to sitagliptin through highly enantioselective Rh(I) catalyzed hydrogenation.
