通过脱氢策略从相应的饱和对应物中直接去除氢的转变是一个梦想的反应,但在很大程度上仍未得到充分探索。在本报告中,首次描述了一种通过分子内 HAT 的简单而稳健的钴肟催化光化学脱氢策略。该反应通过分子内自由基易位进行,然后进行钴辅助脱氢,不需要任何其他外部光敏剂、贵金属或氧化剂。通过这种方法,以中等至优异的产率获得了一系列有价值的不饱和化合物,例如α,β-不饱和酰胺、烯酰胺以及烯丙型和高烯丙型磺酰胺,具有良好的化学和区域选择性,并且通过一系列转化证明了合成的多功能性。并讨论了该方法的机理研究。
Diethylphosphine Oxide (DEPO): High-Yielding and Facile Preparation of Indolones in Water
作者:Tanweer A. Khan、Régis Tripoli、James J. Crawford、Concepcion G. Martin、John A. Murphy
DOI:10.1021/ol035173i
日期:2003.8.1
[reaction: see text] Indolones are prepared in excellent yield at 80 degrees C in water by radical reaction (aryl radical formation, hydrogen atom abstraction, cyclization, and rearomatization) mediated by the reagent diethylphosphine oxide (DEPO). The reaction features V-501 as a water-soluble initiator; no other additives are needed. The process proceeds at a much lower temperature than is required
nitrenium (NHN) salts, the analogues of N-heterocyclic carbenes, have attracted considerable interest. However, relatively little is known about their catalytic ability beyond their Lewis acid catalysis. Herein, we describe that NHNs can serve as catalytic electron acceptors for charge transfer complex photoactivations. We showcase that, under blue light irradiation, the NHN salts could catalyze the
halogen bonding (XB) for the generation of aryl radicals from aryl halides under blue light irradiation and applied it in radical generation/1,5-hydrogen-atom transfer/radical cyclization cascade reactions for the synthesis of oxindoles and isoindolinones. On the basis of experimental studies, we propose that DBU can serve as a suitable XB acceptor with aryl halides for the formation of a photoactive
Synthesis, Structure, and Chemoselective Reactivity ofN-(2-Iodylphenyl)acylamides: Hypervalent Iodine Reagents Bearing a Pseudo-Six-Membered Ring Scaffold
作者:Uladzimir Ladziata、Alexey Y. Koposov、Ka Y. Lo、Jeff Willging、Victor N. Nemykin、Viktor V. Zhdankin