Iodine(V) Reagents in Organic Synthesis. Part 3. New Routes to Heterocyclic Compounds via <i>o</i>-Iodoxybenzoic Acid-Mediated Cyclizations: Generality, Scope, and Mechanism
作者:K. C. Nicolaou、P. S. Baran、Y.-L. Zhong、S. Barluenga、K. W. Hunt、R. Kranich、J. A. Vega
DOI:10.1021/ja012126h
日期:2002.3.1
The discovery and development of the o-iodoxybenzoic acid (IBX) reaction with certain unsaturated N-aryl amides (anilides) to form heterocycles are described. The application of the method to the synthesis of delta-lactams, cyclic urethanes, hydroxy amines, and amino sugars among other important building blocks and intermediates is detailed. In addition to the generality and scope of this cyclization
A CuCl2-promoted alkene aminochlorination reaction has been developed. A variety of anilides that contain a mono-, di-, or trisubstituted alkenyl moiety readily participated in this reaction to afford structurally diverse vicinal chloroamines. Studies suggest that the process proceeds by a radical-type mechanism and that CuCl2 serves as both the oxidant to generate the amidyl radical as well as the
important amidyl radicals from N−H amides is an appealing and yet challenging task. Previous methods require a stoichiometric amount of a strong oxidant and/or a costly noble‐metal catalyst. We report herein the first electrocatalytic method that employs ferrocene (Fc), a cheap organometallic reagent, as the redox catalyst to produce amidyl radicals from N‐aryl amides. Based on this radical‐generating
of nitrogen‐centered radicals, generated through electrochemical oxidation, to alkenes followed by trapping of the cyclized radical intermediate with 2,2,6,6‐tetramethylpiperidine‐N‐oxyl radical (TEMPO). Difunctionalization of a variety of alkenes with easily available carbamates/amides and TEMPO affords aminooxygenation products in high yields and with excellent trans selectivity for cyclic systems
A copper‐catalyzed oxidative amination of unactivated internal alkenes has been developed. The Wacker‐type oxidative alkene amination reaction is traditionally catalyzed by a palladiumthrough a mechanism involving aminopalladation and β‐hydride elimination. Replacing the precious and scarce palladium with a cheap and abundant copper for this transformation has been challenging because of the difficulty