作者:Benjamin D. A. Shennan、Peter W. Smith、Yusuke Ogura、Darren J. Dixon
DOI:10.1039/d0sc03676e
日期:——
An efficient three-step sequence to afford a valuable class of spirocyclic pyrrolidines is reported. A reductive cleavage/Horner–Wadsworth–Emmons cascade facilitates the spirocyclisation of a range of isoxazolines bearing a distal β-ketophosphonate. The spirocyclisation precursors are elaborated in a facile and modular fashion, via a [3 + 2]-cycloaddition followed by the condensation of a phosphonate
报道了提供有价值的螺环吡咯烷类的有效三步序列。还原性裂解/霍纳-沃兹沃思-埃蒙斯级联反应促进一系列带有远端β-酮膦酸酯的异恶唑啉的螺环化。螺环化前体通过[3 + 2]-环加成反应,然后通过膦酸酯的缩合,引入多个发散点,以简便且模块化的方式进行制备。该协议的合成效用已在广泛的1-azaspiro [4,4]壬烷家族的合成中以及在天然产物(±)-头孢他辛的简明形式合成中得到了证明。