No abstract

Donor-acceptor cyclopropanes are reacted under the influence of a Lewis acid with hydrazonyl chlorides to afford tetrahydropyridazines. Formally, this transformation can be regarded as a [3 + 3]-cycloaddition of three-membered rings and nitrile imines generated in situ. This efficient method provides fast access to a variety of structurally diverse pyridazine derivatives. The structure of a typical product was confirmed by X-ray crystallography.

We describe the first electrochemical activation of D–A cyclopropanes and D–A cyclobutanes leading after C(sp3)−C(sp3) cleavage to the formation of highly reactive radical cations. This concept is utilized to formally insert molecular oxygen after direct or DDQ‐assisted anodic oxidation of the strained carbocycles, delivering β‐ and γ‐hydroxy ketones and 1,2‐dioxanes electrocatalytically. Furthermore, insights into the mechanism of the oxidative process, obtained experimentally and by additional quantum‐chemical calculations are presented. The synthetic potential of the reaction products is demonstrated by diverse derivatizations.

The first (3+ +3)-annulation process of donoracceptor cyclopropanes using synergistic catalysis is reported. The Rh 2 (OAc) 4 -catalyzed decomposition of diazoc arbonyl compounds generated carbonyl ylides in situ. These 1,3dipoles were converted with donor-acceptor cyclopropanes, activated by Lewis acid catalysis,toaffordmultiply substituted pyran scaffolds in high yield and diastereoselectivity.Extensive optimization studies enabled access to 9-oxabicyclo-[3.3.1]nonan-2-one and 10-oxabicyclo[4.3.1]decen-2-ol cores, exploiting solvent effects on intermediate reactivity.

Deuterium-labeled compounds find wide applications in kinetic studies, and within the pharmaceutical industry.A ne asily removable pyrimidine-baseda uxiliary has been employedf or the meta-CÀHd euteration of arenes. The scope of this Pd-catalyzedd euteration using commerciallya vailable[ D 1 ]-and[ D 4 ]-acetic acid has been demonstrated by its application in phenylacetic acid and phenylmethanesulfonate derivatives. Ad etailed mechanistic study led us to explore the reversibility of the non-rate determining CÀHa ctivation step. The presents tudy of meta-deuteriumi ncorporation illustrates the template morphology in terms of selectivity.T he applicability of this method has been demonstrated by the selective deuterium incorporation into various pharmaceuticals.