The preparation of new chiral N, N′-disubstituted 1, 2, 4-triazolium based NHC salt precursors, Ia′ and Ib, from phenylhydrazine and l-phenylalanine is reported. The 1, 3, 4- trisubstituted triazolium salt Ia′ was obtained by a stepwise ring construction from l- phenylalanine via the corresponding imino ether and acetohydrazonamide, while a heterocyclic O-/N-heteroatom exchange strategy, based on a ring-opening/ring-closure of ...
