Department of Chemistry, Indian Institute of Technology, Kharagpur, India.
Org Lett. 2011 Mar 4;13(5):888-91. doi: 10.1021/ol102861j. Epub 2011 Feb 8.
Bispropargyl sulfones equipped with aromatic rings of dissimilar nature were synthesized. Under basic conditions, these sulfones isomerized to the bisallenic sulfones, creating a competitive scenario between two alternate Garratt-Braverman (GB) cyclization pathways. The observed product distribution ruled out the involvement of any ionic intermediate and supported the diradical mechanism with greater involvement of the electron-rich aromatic ring via the more nucleophilic radical. DFT-based calculations supported the diradical mechanism along with the observed selectivity.
合成了带有不同性质芳环的双炔丙基砜。在碱性条件下，这些砜异构化为双烯丙基砜，在两种替代的Garratt-Braverman（GB）环化途径之间形成了竞争局面。观察到的产物分布排除了任何离子中间体的参与，并支持通过更亲核的自由基，电子富芳环更大程度参与的双自由基机理。基于密度泛函理论（DFT）的计算支持了双自由基机理和观察到的选择性。
