| |
[摘要]：A powerful aminobenzannulation reaction has been applied for the synthesis of amino-substituted quinolines, dibenzofurans, and carbazoles. The precursors are heterocycles bearing an acetyl group ortho to an internal alkyne, which are com. available or can be obtained in three to four classical and efficient reactions: Vilsmeier-Haack, Sonogashira (diversity point), Grignard, and Ley's oxidn. Upon aminobenzannulation reaction (classical conditions being pyrrolidine neat or in a solvent and 4A MS), an interesting range of disubstituted quinolines, dibenzofurans, and carbazoles are obtained along with enamine formation in some cases. The reaction is useful since meta-substituted heterocycles are produced and also differs from classical heterocyclic methods which go through closure at the heteroatom-contg. ring instead of benzene ring formation. |
|
