Yulia A. Volkova

Duality of Donor–Acceptor Cyclopropane Reactivity as a Three‐Carbon Component in Five‐Membered Ring Construction: [3+2] Annulation Versus [3+2] Cycloaddition

Quo vadis? The Lewis acid catalyzed reaction of (hetero)aryl-derived donor-acceptor cyclopropanes with alkenes can be selectively directed along a [3+2] annulation pathway (see scheme). This new process provides convenient and efficient access to indanes and other cyclopentannulated (hetero)arenes, among which polyoxygenated 1-arylindanes exhibit significant cytotoxicity against several cancer cell lines with an IC50 of 10(-6)-10(-5)  M.

Copper(II)-Mediated Aerobic Synthesis of Imidazo[1,2-a]pyridines via Cascade Aminomethylation/Cycloisomerization of Alkynes.

A single copper(II)-catalyzed three-component cascade aminomethylation/cycloisomerization of propiolates to form imidazo[1,2-a]pyridines was explored. A straightforward method was developed for the practical synthesis of functionalized imidazo[1,2-a]pyridines from benzaldehydes, 2-aminopyridines, and propiolate derivatives catalyzed by Cu(OAc)2 hydrate in the presence of air. The protocol is marked by excellent yields, functional group tolerance, and, above all, adaptability to synthesize imidazo[1,2-a]pyridine-based drug molecules such as Alpidem.

Unexpected Heterocyclization of Electrophilic Alkenes by Tetranitromethane in the Presence of Triethylamine. Synthesis of 3-Nitroisoxazoles

Novel reaction of tetranitromethane (TNM) with electrophilic alkenes in the presence of triethylamine yielding substituted 3-nitroisoxazoles was found and studied. Triethylamine increases the reactivity of TNM toward electrophilic alkenes promoting their heterocyclization, and the reactions proceed in an unusual way. A variety of alpha,beta-unsaturated aldehydes, ketones, esters, amides, phosphonates, and nitro and sulfur compounds was involved in the heterocyclization reaction, and a wide range of functionalized 3-nitroisoxazoles was obtained in good to high yields. The scope and limitations of the reaction and the mechanistic aspects are discussed.

A Straightforward Approach toward Multifunctionalized Pyridazines via Imination/Electrocyclization

A facile synthesis of functionalized 3-carbamide pyridazines starting from readily available chlorovinyl aldehydes and oxamic acid thiohydrazides via cascade imination/electrocyclization is reported. In the presence of p-toluenesulfuric acid, various ketones have been efficiently incorporated into the pyridazine derivatives through a two-step sequence involving a Vilsmeier-Haack reaction and imination. The synthetic value of this method has been demonstrated by efficient synthesis of steroidal pyridazines.

CCDC 1402494: Experimental Crystal Structure Determination

Related Article: Alexander V. Komkov, Anna S. Komendantova, Leonid G. Menchikov, Elena I. Chernoburova, Yulia A. Volkova, Igor V. Zavarzin|2015|Org.Lett.|17|3734|doi:10.1021/acs.orglett.5b01718