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.

Practical and regioselective halonitrooxylation of olefins to access β-halonitrates

Organic nitrates, as effective donors of the signaling molecule nitric oxide, are widely applied in the pharmaceutical industry. However, practical and efficient methods for accessing organic nitrates are still scarce, and achieving high regiocontrol in unactivated alkene difunctionalization remains challenging. Here we present a simple and practical method for highly regioselective halonitrooxylation of unactivated alkenes. The approach utilizes TMSX (X: Cl, Br, or I) and oxybis(aryl-λ3-iodanediyl) dinitrates (OAIDN) as sources of halogen and nitrooxy groups, with 0.5 mol % FeCl3 as the catalyst. Remarkably, high regioselectivity in the halonitrooxylation of aromatic alkenes can be achieved even without any catalyst. This protocol features easy scalability and excellent functional group compatibility, providing a range of β-halonitrates (127 examples, up to 99% yield, up to >20:1 rr). Notably, 2-iodoethyl nitrate, a potent synthon derived from ethylene, reacts smoothly with a variety of functional units to incorporate the nitrooxy group into the desired molecules.

From α-keto acids to nitrile oxides enabled by copper nitrate: a facile access to fused isoxazolines

An unprecedented generation of nitrile oxides was developed from α-keto acids and copper nitrate through a novel carbon–carbon bond cleavage mode, affording pharmacologically interesting fused isoxazolines via 1,3-dipolar cycloadditions.

Zinc-catalyzed asymmetric nitrooxylation of β-keto esters/amides with a benziodoxole-derived nitrooxy transfer reagent

Zinc-catalyzed asymmetric nitrooxylation to afford a series of α-nitrooxy β-keto esters/amides in high yields and with low to moderate enantioselectivities has been disclosed.

From Alkenes to Isoxazolines via Copper-Mediated Alkene Cleavage and Dipolar Cycloaddition

An unprecedented copper-mediated anion transformation is reported, along with selective C═C double bond cleavage and dipolar cycloaddition reaction from simple alkenes and inexpensive copper nitrate. Various transformations demonstrate the generality of this method. Further mechanistic investigation indicates a novel ionic pathway for alkene cleavage and highlights the coeffect of iodide and boric acid as additives on the inhibition of well-documented competitive nitration byproducts.

N-Thiocyanato-dibenzenesulfonimide: a new electrophilic thiocyanating reagent with enhanced reactivity

N-Thiocyanato-dibenzenesulfonimide: a new electrophilic thiocyanating reagent was readily prepared and exhibited enhanced reactivity with a wide scope of substrates.

Copper nitrate-mediated synthesis of 3-aryl isoxazolines and isoxazoles from olefinic azlactones

A copper nitrate-mediated [2 + 2 + 1] cycloaddition reaction was developed for the expedient synthesis of isoxazolines and isoxazoles from olefinic azlactones.