School of Chemistry, University of Hyderabad , Hyderabad 500046, India.
Org Lett. 2016 Jul 1;18(13):3066-9. doi: 10.1021/acs.orglett.6b01149. Epub 2016 Jun 22.
An unprecedented metal-free dimethyl sulfoxide (DMSO) and N-iodosuccinimide mediated regioselective 5-exo-dig oxidative cyclization of an in situ generated enol equivalent of amides from ynamides bearing internal alkynes is demonstrated. The reaction allows easy access to functionalized pyrrolidone skeletons. Pyrrolidones having 3-o-biaryl motifs successfully undergo intramolecular electrophilic cyclization with the α,β-unsaturated olefin, furnishing spiro-pyrrolidone motifs. A one-pot sequential 5-exo-dig cyclization of the yne-tethered ynamides, followed by electrophilic cyclization of the pyrrolidone, is presented. The role of DMSO in the transformation is clarified, and a tentative reaction pathway is proposed.
一种前所未有的无金属二甲亚砜（DMSO）和 N-碘代丁二酰亚胺介导的区域选择性 5-endo- dig 氧化环化反应，由内炔基取代的炔酰胺原位生成的烯醇等价物进行。该反应可轻松获得官能化的吡咯烷酮骨架。具有 3-o-联芳基结构的吡咯烷酮成功地与α,β-不饱和烯烃进行分子内亲电环化反应，生成螺吡咯烷酮结构。提出了一种炔基连接的炔酰胺的一锅顺序 5-endo- dig 环化，然后进行吡咯烷酮的亲电环化。澄清了 DMSO 在转化中的作用，并提出了一个推测的反应途径。
