Direct Nitration of Vinylcycles with Copper Nitrate

1,3-Difunctionalization of Donor-Acceptor Cyclopropanes Enabled by Copper Nitrate: A Direct Approach to γ-Halonitrates

1,3-Difunctionalization of donor-acceptor cyclopropanes with copper nitrate and N-halosuccinimide was developed to efficiently afford γ-halonitrates. The pivotal factor of this protocol lies in the dual role of copper nitrate as a Lewis acid and an ideal nitrooxy source. The given approach features easy handling, good functional group compatibility, and wide substrate scope. Furthermore, various transformations of the obtained γ-chloronitrates underscore the remarkable synthetic potential inherent in this method.

Rongalite/iodine-mediated C(sp3)-H bond oximation and thiomethylation reaction of methyl ketones using copper nitrate as the [NO] reagent: synthesis of thiohydroximic acids

In this work, a highly efficient rongalite/iodine-mediated oxime formation reaction for the preparation of thiohydroximic acids from methyl ketones by employing copper nitrate as the [NO] reagent has been developed. Notably, copper nitrate participated as both a catalyst and the mild oximation reagent in the transformation. This reaction is highly efficient and facile, with a broad substrate scope, especially for fused ring skeleton substrates, heterocyclic skeleton substrates, and acetyl-substituted natural products. Mechanistic studies revealed that copper nitrate might be converted into a NO2 radical or the NO2 radical dimeric forms as an ion-pair equivalent to participate in the transformation.

Site-selective direct nitration of 2H-indazoles: easy access to 7-nitroindazoles

A new site-selective methodology for C-H nitration of 2H-indazoles has been accomplished at the C7 position using iron(III) nitrate. This strategy enables practical access to an array of 7-nitroindazoles with broad functional group tolerance in good yields. The synthesized products have been proven as valuable synthetic intermediates by demonstrating the synthetic utility. Mechanistic investigations indicate that the reaction goes through a radical pathway.

DNDMH-mediated direct nitration of aryl alkenes

N-nitro type reagents have been demonstrated as mild nitration tools in recent years. This work presents an exploration of direct nitration of aryl alkenes mediated by DNDMH, a novel N-nitro type reagent developed in our previous study. It exhibits herein a new property of DNDMH as an effective direct nitration reagent for aryl alkenes, through probably the delivery of nitro radicals with the aid of TEMPO and Cu(OAc)2.

AlCl3-mediated ring-opening reactions of indoline-2-thiones with acyl cyclopropanes, bi-cyclopropanes and spirocyclic cyclopropanes

AlCl3-mediated nucleophilic ring-opening reactions of indoline-2-thiones with various acyl cyclopropanes, bi-cyclopropanes and spirocyclic cyclopropanes were investigated. A series of ketones functionalized with indolylthio groups were synthesized in yields ranging from moderate to good. Moreover, chemical transformations of 4-indolylthio butan-1-ones to dihydro-2H-thiepino[2,3-b]indoles and sulfone were carried out to further expand both synthetic utility and structural complexity.