Copper‐Catalyzed Oxidative Carbamoylation of N‐Arylacrylamides with Hydrazinecarboxamides Leading to 2‐(Oxindol‐3‐yl)acetamides

Abstract

A tandem radical carbamoylation/cyclization reaction of N‐arylacrylamides with hydrazinecarboxamides has been developed for facile access to 2‐(oxindol‐3‐yl)acetamides, which had been utilized as precursors in the synthesis of natural bioactive pyrrolidinoindolines. In the presence of 1 mol% of copper(II) carbonate and 4 equiv. of tert‐butyl hydroperoxide, a wide range of N‐arylacrylamides underwent highly regioselective carbamoylation with hydrazinecarboxamides followed by 5‐exo‐trig cyclization to afford structurally diverse 2‐(oxindol‐3‐yl)acetamides in moderate to excellent yields.magnified image

Direct Carbamoylation of Quinoline N‐oxides with Hydrazinecarboxamides via C−H Bond Activation Catalyzed by Copper Catalyst

“…Based on the above experimental results and previous reports, [16] a possible reaction pathway was proposed as shown in Scheme 3. Firstly, carbamoyl radical 2 generated from the reaction of hydrazinecarboxamide with TBHP.…”

“…Although various reactions for the synthesis of quinoline derivatives have been realized, trying to develop new versatile and practical methods are still desirable. Recently, Tian's group realized carbamoylation of N ‐arylacrylamides and nitrogen heteroarenes using hydrazinecarboxamides as substrates . Encouraged by Tian's work and on the basis of our continued pursuit of C−H bond activation, herein we disclose a new strategy to access carbamoylated quinolone N ‐oxides via CuBr‐catalyzed carbamoylation of quinolone N‐oxides with hydrazinecarboxamides.…”

“…Only 16-57% yields of the product was isolated when other solvents (CH 3 CN, DMF, PhCl, Toluene) were used ( Table 1, entries [10][11][12][13]. Encouraged by this result, various oxidants were further investigated and performed with lower yields in this reaction ( Table 1, entries [14][15][16]. Finally, the best yield of P1(92%) was obtained by employing CuBr as catalyst and TBHP as oxidant in DMSO under air.…”

Photocatalytic Cascade Radical Cyclization Approach to Bioactive Indoline-Alkaloids over Donor–Acceptor Type Conjugated Microporous Polymer

“…Retrosynthetic analysis indicated that the aforementioned valuable alkaloids share the same building block, 3-formyloxindoles (Figure ). Although considerable efforts for constructing 3-functional-oxindoles have been made, short synthesis of 3-formyloxindole structure from low-cost and readily available starting materials under mild conditions are rare. The formyl group provides a handle for chemical transformations because of its rich chemical reactivity .…”

Palladium-Catalyzed Carbonylative Synthesis of α,β-Unsaturated Amides from Styrenes and Nitroarenes

“…α,β-Unsaturated amides are an important structural motif that is present in a wide range of natural products, pharmaceuticals, and polymeric materials . Additionally, α,β-unsaturated amides also serve as versatile building blocks in organic synthesis . They are not only viable for further functionalization but also active for reactions such as nucleophilic addition and pericyclic reactions.…”