Pyrrolodiazines. 6. Palladium-catalyzed arylation, heteroarylation, and amination of 3,4-dihydropyrrolo[1,2-a]pyrazines

J Org Chem. 2004 Dec 10;69(25):8668-75. doi: 10.1021/jo048898o.

Abstract

The palladium-catalyzed Suzuki cross-coupling reaction of arylboronic acids and 6-bromo- and 6,8-dibromo-3,4-dihydropyrrolo[1,2-a]pyrazines afforded 6-substituted and 6,8-disubstituted 3,4-dihydropyrrolo[1,2-a]pyrazines in good yields. Stille and Negishi coupling reactions have been used to prepare 6-heteroaryl-substituted derivatives in moderate yields by employing heteroaryl halides and 6-metalated 3,4-dihydropyrrolo[1,2-a]pyrazines as reaction partners. A variety of cyclic secondary amines have also been incorporated at position C-6 of 6-bromo-1-phenyl-3,4-dihydropyrrolo[1,2-a]pyrazine in the presence of the palladium catalyst Pd(2)(dba)(3) in conjunction with BINAP as ligand. This amination reaction is one of the few reported examples of such a palladium-catalyzed transformation on a pyrrole ring, although the reaction could not be extended to less nucleophilic amines.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkylation
  • Amination
  • Catalysis
  • Molecular Structure
  • Palladium / chemistry*
  • Pyrazines / chemical synthesis*
  • Pyrazines / chemistry
  • Pyrroles / chemical synthesis*
  • Pyrroles / chemistry

Substances

  • Pyrazines
  • Pyrroles
  • Palladium