Mild Radical Oxidative sp(3)-Carbon-Hydrogen Functionalization: Innovative Construction of Isoxazoline and Dibenz[b,f]oxepine/azepine Derivatives

作者：Gini Andrea; Mancheno Olga Garcia

来源：Synlett, 2016, 27(4): 526-539.

DOI：10.1055/s-0035-1560908

• carbon-hydrogen functionalization
• oxidations
• radicals
• peroxides
• heterocycles

Direct carbon-hydrogen bond functionalization has emerged as a powerful synthetic method for the straightforward and modular functionalization of organic molecules. In this account, we described our latest contributions in the area of oxidative sp(3)-carbon-hydrogen bond functionalization using mild radical oxidants for the construction of structurally important heterocycles. We have developed two new methodologies in which a new class of substrate and an uncommon nucleophilic reagent have been introduced to the existing palette of reaction partners for oxidative carbon-hydrogen functionalization. To achieve these results, the 2,2,6,6-tetramethylpiperidinyloxyl (TEMPO) radical and a benzoyl peroxide/copper(I) system have been employed as oxidants for the dehydrogenative one-pot synthesis of N-alkoxycarbonyl-protected isoxazolines from hydroxylamines and for the synthesis of dibenz[b,f]oxepines, dibenzo[b,f]thiepines, and dibenz[b,f]azepines from simple xanthenes, thioxanthenes, and acridanes, respectively. 1 Introduction 2 2,2,6,6-Tetramethylpiperidinyloxyl-Mediated Dehydrogenative Formation and Trapping of Unstable Nitrones: Synthesis of N-Alkoxycarbonyl-Protected Isoxazoline Derivatives 3 Oxidative sp(3)-Carbon-Hydrogen Bond Functionalization and Ring Expansion with Trimethylsilyldiazomethane: Synthesis of Dibenzoxepines, Dibenzothiepines, and Dibenzazepines 4 Conclusions and Outlook

• 出版日期2016-3