An Fe(III)-catalyzed intramolecular N-N coupling of aliphatic azidoamines that forms diverse five-and six-membered semisaturated diazoheterocycles using air as an oxidant is reported, providing an alternative to hydrazine-based methods. Mechanistic studies suggest that a N-radical induced intramolecular homolytic substitution (S(H)2) is involved in ring closure. The power of this N-N bond-forming method is also demonstrated by using it as the final step in a total synthesis of (-)-newbouldine.
One-Pot Synthesis of Macrocycles by a Tandem Three-Component Reaction and Intramolecular [3+2] Cycloaddition
作者:Tracey Pirali、Gian Cesare Tron、Jieping Zhu
DOI:10.1021/ol061782p
日期:2006.8.1
substrates, a programmed sequence involving an alpha-isocyano acetamide-based three-component reaction followed by a copper-catalyzedintramolecular [3+2] cycloaddition of alkyne and azide took place to afford complex macrocycles in moderate to good yields. One macrocycle and two heterocycles were produced with concurrent formation of five chemical bonds in this operationally simple process.