Multigram Synthesis of Trioxanes Enabled by a Supercritical CO<sub>2</sub> Integrated Flow Process
作者:Lingqiao Wu、Bruna L. Abreu、Alexander J. Blake、Laurence J. Taylor、William Lewis、Stephen P. Argent、Martyn Poliakoff、Hamza Boufroura、Michael W. George
DOI:10.1021/acs.oprd.1c00111
日期:2021.8.20
continuous approach using a custom-built high-pressure sapphire photoreactor to synthesize trioxanes via the dearomatization of para-substituted phenols by photogenerated singlet oxygen in supercriticalCO2. CO2 also facilitates mixing with O2 and has lower viscosity, thereby improving penetration into the pores of the solid acid catalyst used for the formation of trioxanes. We show the capabilities
高活性氢过氧化物的光化学合成及其转化为有用的产品,如 1,2,4-三恶烷,在合成有机化学和药物制造中具有广泛的兴趣,特别是因为它们与潜在的抗疟疾和抗癌治疗药物相关,例如,青蒿素。一类抗疟药物基于 1,2,4-三恶烷支架,但由于它们在可氧化溶剂中的不稳定性,以克规模生产此类化合物具有挑战性。此外,目前的方法使用固体氧化剂,这使得连续加工成为问题,或者使用分子氧,需要长达 48 小时的长反应时间。在这里,我们报告了一种新的多克连续方法,使用定制的高压蓝宝石光反应器通过脱芳构化合成三恶烷光生单线态氧在超临界 CO 2 中对位取代的苯酚。CO 2还促进与O 2 的混合并且具有较低的粘度,从而提高对用于形成三恶烷的固体酸催化剂的孔的渗透。我们展示了 5.2 mL 反应器将反应放大到 67 g/天的能力。这种合成方法提供了一个平台,可以在流动条件下快速获取高价值化合物,原子效率高、产率高、反应时间短,并且无需分离危险中间体。
Atom Economical Photocatalytic Oxidation of Phenols and Site-Selective Epoxidation Toward Epoxyquinols
作者:Louis Péault、Aurélien Planchat、Pierrick Nun、Erwan Le Grognec、Vincent Coeffard
DOI:10.1021/acs.joc.1c02459
日期:2021.12.17
The discovery of a multiple-bond-forming process merging the singlet oxygen-mediated dearomatization of 3,4-disubstitued phenols and diastereo- and regioselective epoxidation is described. This one-pot strategy using a transition metal-free multicatalytic system comprised of rose bengal and cesium carbonate allowed the efficient formation of functionalized epoxyquinol products under mild conditions
Oxidative De-aromatization ofpara-Alkyl Phenols intopara-Peroxyquinols andpara-Quinols Mediated by Oxone as a Source of Singlet Oxygen
作者:M. Carmen Carreño、Marcos González-López、Antonio Urbano
DOI:10.1002/anie.200504605
日期:2006.4.21
Photocatalytic Synthesis of <i>para</i>-Peroxyquinols: Total Synthesis of (±)-Stemenone B and (±)-Parvistilbine B
作者:Matthew C. Carson、Brandon J. Orzolek、Marisa C. Kozlowski
DOI:10.1021/acs.orglett.2c02640
日期:2022.10.14
photosensitized singlet oxygen approach functionalized a variety of electronically diverse para-alkyl phenols in 27–99% isolated yields. Utilizing this dearomative oxidation, (±)-stemenone B and (±)-parvistilbine B were synthesized in 9 and 11 steps, respectively, from commercially available starting materials. Additional experiments revealed the dramatic influence of base and solvent on the selectivity