Development of a simple system for the oxidation of electron-rich diazo compounds to ketones

Tris(pentafluorophenyl)borane‐Catalyzed Oxygen Insertion Reaction of α‐Diazoesters (α‐Diazoamides) with Dimethyl Sulfoxide

“…In a word, both electron‐donating and electron‐deficient α‐diazoesters as well as α‐diazoamides could be effective for this protocol, demonstrating its broad substrate scope. These results were in sharp contrast to stoltz's work [4a] that was only limited to several electron‐donating α‐diazoesters and required a very long time (more than 3 days).…”

“…[3] Among these approaches, the direct oxidative denitrogenation of α-diazoesters offers a mild synthetic route to α-ketoesters and their derivatives. [4] However, these methods usually employed environmentally unfriendly stoichiometric oxidants, including dimethyldioxirane (DMDO), [5] diethyl azodicarboxylate (DEAD)/H 2 O, [6] tert-butyl hypochlorite (tBuOCl) [7] and nitrosoarenes. [8] What's more, organic dyes [9] or some toxic and precious metals [10] such as Cu and Rh were also used for these oxidation reactions.…”

A three-membered ring approach to carbonyl olefination

“…When the reaction is performed in DMSO, benzophenone is obtained in 43% yield (Fig. 6b ) 36 . These results provide evidence for the formation of a diazo compound through cheletropic elimination.…”

Syntheses of 2-Iminoindolin-3-ones and 2-Alknyl-2,3-dihydroquinazolin-4(1H)-ones from 3-Diazoindolin-2-imines

“…We assumed that nitrone worked as an oxygen transfer reagent at the beginning of the reaction. Thus, the combination of N -oxide (e.g., 2,6-dichloropirydine N -oxide) and imine was used instead of nitrone to react with 1a . The reaction was tested under standard conditions, and 3a was obtained in 71% yield (Scheme , eq 1).…”