Synthetic Building Blocks Containing the 1,2-Diazine Moiety: N- and O-Protected 3-(4-Pyridazinyl)isoserines

Synthesis of Chiral Diazine and Pyridine Sulfoxides. Asymmetric Induction by Chiral Sulfoxides in an “Aromatic Ortho-Directed Metalation−Reaction with Electrophiles Sequence”. Diazines. 24

“…We report here ortho -directed metalations in the π-deficient heterocyclic series (pyridazine, pyrimidine, and pyridine) using an aryl sulfoxide as a chiral ortho -directing group. In aliphatic series, many papers have described asymmetric induction on sp 3 carbon substituted by a chiral sulfoxide during a metalation and reaction with electrophiles process. − Very few publications have reported metalations of aromatic rings followed by asymmetric inductions during reaction of the lithio compound with a prochiral electrophile; de's in the range 10−83% have been obtained. − The only reference with sulfur derivatives is that of H. Takahashi who obtained up to 82% de using chiral sulfonamides.…”