Does electrophilic activation of nitroalkanes in polyphosphoric acid involve formation of nitrile oxides?
作者:Alexander V. Aksenov、Nicolai A. Aksenov、Nikita K. Kirilov、Anton A. Skomorokhov、Dmitrii A. Aksenov、Igor A. Kurenkov、Elena A. Sorokina、Mezvah A. Nobi、Michael Rubin
DOI:10.1039/d1ra06503c
日期:——
The mechanistic rationale involving activation of nitroalkanes towards interaction with nucleophilic reagents in the presence of polyphosphoricacid (PPA) was re-evaluated. Could nitrile oxide moieties be formed during this process? This experiment demonstrates that at least in some cases this could happen, as generated nitrile oxides were successfully intercepted as adducts of [3 + 2] cycloadditions
Synthesis of Furoxans and Isoxazoles via Divergent [2 + 1 + 1 + 1] Annulations of Sulfoxonium Ylides and <sup>t</sup>BuONO
作者:Zhonghe Tang、Yao Zhou、Qiuling Song
DOI:10.1021/acs.orglett.9b01876
日期:2019.7.5
isoxazoles in which the [2 + 1 + 1 + 1] annulation reaction of sulfoxonium ylides is reported for the first time. When the reaction was performed using tBuONO as the nitrogen source without metal catalyst, the desired furoxans were obtained in decent yields with wide substrate scope. Isoxazoles bearing three carbonyl groups were achieved when the reaction was conducted using Cu(TFA)2 as catalyst.