Diversity-Oriented Synthesis of Spiropentadiene Pyrazolones and 1<i>H</i>-Oxepino[2,3-<i>c</i>]pyrazoles from Doubly Conjugated Pyrazolones via Intramolecular Wittig Reaction
作者:Pankaj V. Khairnar、Chi-Yi Wu、Yi-Fang Lin、Athukuri Edukondalu、Yi-Ru Chen、Wenwei Lin
DOI:10.1021/acs.orglett.0c01552
日期:2020.6.19
An efficient method for the diversity-oriented synthesis of spiropentadiene pyrazolones and 1H-oxepino[2,3-c]pyrazoles is reported. The methodology attributes O-acylation of phosphorus zwitterions which were formed by a tandem phospha-1,6-addition of PBu3 to α,β,γ,δ-unsaturated pyrazolones, further generating betaine intermediates that preferentially resulted in the aforementioned cyclic products in
报道了一种高效的方法来合成螺环戊二烯吡唑啉酮和1 H-氧代庚并[2,3- c ]吡唑。该方法学归因于将PBu 3串联磷酸1,6-加成到α,β,γ,δ-不饱和吡唑酮上形成的两性磷的O-酰化作用,进一步产生了甜菜碱中间体,该中间体优先产生上述环状产物以多元化为导向的方式。机理研究表明,甜菜碱的形成是通过分子内维蒂希反应或空前的δ- C-酰化/环化/维蒂希反应提供产物的关键步骤。