Related Article: Jijun Chen, Wenhao Long, Yonggang Yang, Xiaobing Wan|2018|Org.Lett.|20|2663|doi:10.1021/acs.orglett.8b00867

A novel, secondary amide activation strategy has been developed through the in situ generation of ylides from amides and diazoacetates. Under the developed reaction conditions, Mn-catalyzed ylide formation and interception reaction by sulfonamide delivered a variety of N-sulfonylamidines. Notably, when highly active Zn(OTf)(2) was used as the catalyst, further N-H insertion products were obtained. In contrast with traditional methods, our amide activation strategy is distinguished by accessible starting material, inexpensive catalyst, and broad substrate scope.

In this account, we describe our recent progress on transition-metal-free-catalyzed cross-coupling reactions using tetrabutylammonium iodide (TBAI) as the catalyst and tert-butyl hydroperoxide (TBHP) as the oxidant. A rich variety of important organic compounds including α-acyloxy ethers, tert-butyl peresters, allylic esters, amides, α-amino nitriles, fully substituted pyrazoles, N-sulfonyl formamidines, α-amino acid esters, cyanomethyl esters, N-nitrosamines, and 3-acyloxy-2,3-dihydrobenzofurans have been successfully achieved in high chemoselectivity. Mechanistic studies suggested that TBAI could decompose TBHP to t BuO. and t BuOO. or be oxdized to (hypo)iodite by TBHP.

A novel generation of oxazole ylide and interception with sulfonamide have been well developed to construct fully substituted amidines. This copper-catalyzed four-component reaction incorporates two diazo molecules to target amidines and shows broad substrate scope, excellent functional groups tolerance and good to excellent yields.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Through the interception of amide ylides with sulfonamides, we herein report the first general example of an intermolecular condensation reaction between sulfonamides and amides. Beyond formamides, this approach was successfully applied to a variety of lactams and linear amides, giving rise to a broad array of (E)-N-sulfonyl amidines.

A novel in situ generation of nitrilium from a nitrile ylide and the subsequent Mumm rearrangement of carboxylic acid, nitrile, and diazo compounds gave various unsymmetrical diacylglycine esters in moderate to high yields. This copper-catalyzed cascade reaction enables one-pot generation of two C-N bonds, one C[double bond, length as m-dash]O bond, and one C-H bond, with nitrogen as the only byproduct. The reaction has a broad functional-group tolerance, is rapid, easily scales up to the 100 mmol scale, and is insensitive to air and moisture.

A new coupling reaction between 2-vinylphenols and carboxylic acids was developed to synthesize 3-acyloxy-2,3-dihydrobenzofurans using Bu4NI as a catalyst and t-BuOOH as an oxidant. This simple and practical methodology is notable due to the ability to complete it under metal-free conditions, with easily available precursors, resulting in a product with high atom economy and high functional group tolerance. Upon the basis of experimental observations and literature, a plausible mechanism is proposed.

A novel strategy has been developed for the highly chemo- and stereo-selective synthesis of (Z)-β-perfluoroalkyl enaminones from readily available starting materials via a multicomponent radical reaction involving sequential fluoroalkylation and Kornblum-DeLaMare reaction. Notably, this methodology involves the concurrent cleavage of at least three chemical bonds, including two C-F bonds and one C-X (X = Br or I) bond, as well as the formation of three new bonds, including one C=O bond, one C=C bond and one C-N bond, in one pot.

The interception of cobalt-based carbene radicals with α-aminoalkyl radicals was combined with the Kornblum-DeLaMare reaction and provides β-ester-γ-amino ketones, which are otherwise difficult to obtain in high chemoselectivity. Mechanistically, this transformation is an interplay of cobalt-based carbene radicals, organoradicals, and ionic intermediates and involves the construction of two C-C bonds and one C=O bond in a one-pot process. The reaction also features a wide substrate scope and is highly efficient and insensitive to moisture and air.

A Co-catalyzed reaction for the construction of 1,4-dicarbonyls has been reported in which cascade organocobalt addition/trapping/Kornblum-DeLaMare rearrangement were involved. In view of the easy availability of starting materials, wide substrate scope, high functionality tolerance, and operational simplicity, this protocol constituted a simple, practical, and powerful alternative compared with previous approaches.

Eine Tandemreaktion für den Aufbau von β-Ester-γ-aminoketonen kombiniert Carbenradikale, organische Radikale und eine ionische Kornblum-DeLaMare-Reaktion in einem einzigen Katalysezyklus. In ihrer Zuschrift auf S. 1247 ff. zeigen X. Wan und Mitarbeiter, dass das Cobalt-basierte Carbenradikal statt einer einfachen Addition an ein Olefin mit α-Aminoalkylradikalen abgefangen werden kann.

A mild and rapid approach has been developed for the construction of fully substituted pyrazoles using TBAI as a catalyst and TBHP as an oxidant, in which tosylhydrazide functions as the ring component and sulfonyl precursor. This protocol features a wide substrate scope with a broad range of functional group tolerance, utilizes easily available starting materials, can be scaled-up, and is operationally simple.