Synthesis of substituted 3,9-diazaspiro[5.5]undecanes via spirocyclization of pyridine substrates
作者:Sharavathi G. Parameswarappa、F.C. Pigge
DOI:10.1016/j.tetlet.2011.06.055
日期:2011.8
Construction of 3,9-diazaspiro[5.5]undecane derivatives can be easily achieved via intramolecular spirocyclization of 4-substituted pyridines. The reaction entails in situ activation of the pyridine ring with ethylchloroformate followed by intramolecular addition of an attached β-dicarbonyl nucleophile in the presence of Ti(OiPr)4.
3,9-二氮杂螺[5.5]十一烷衍生物的构建可以通过分子内4-取代吡啶的螺环化来轻松实现。该反应需要用氯甲酸乙酯原位活化吡啶环,然后在Ti(O i Pr)4存在下分子内添加连接的β-二羰基亲核试剂。