Application of BF3·Et2O in the synthesis of cyclic organic peroxides (microreview)

1-(2-Benzyl-1,5-dimethyl-6,7,8-trioxabicyclo[3.2.1]octan-2-yl)ethan-1-ol

The title compound, 1-(2-Benzyl-1,5-dimethyl-6,7,8-trioxabicyclo[3.2.1]octan-2-yl)ethan-1-ol, was synthesized for the first time by the selective reduction in keto ozonide under the action of the strong reducing agent LiAlH4. The product was characterized by NMR, IR, HRMS, and elemental analysis.

Inverse α-Effect as the Ariadne's Thread on the Way to Tricyclic Aminoperoxides: Avoiding Thermodynamic Traps in the Labyrinth of Possibilities

Stable tricyclic aminoperoxides can be selectively assembled via a catalyst-free three-component condensation of β,δ'-triketones, H₂O₂, and an NH-group source such as aqueous ammonia or ammonium salts. This procedure is scalable and can produce gram quantities of tricyclic heterocycles, containing peroxide, nitrogen, and oxygen cycles in one molecule. Amazingly, such complex tricyclic molecules are selectively formed despite the multitude of alternative reaction routes, via equilibration of peroxide, hemiaminal, monoperoxyacetal, and peroxyhemiaminal functionalities! The reaction is initiated by the "stereoelectronic frustration" of H₂O₂ and combines elements of thermodynamic and kinetic control with a variety of mono-, bi-, and tricyclic structures evolving under the conditions of thermodynamic control until they reach a kinetic wall created by the inverse α-effect, that is, the stereoelectronic penalty for the formation of peroxycarbenium ions and related transition states. Under these conditions, the reaction stops before reaching the most thermodynamically stable products at a stage where three different heterocycles are assembled and fused at the acyclic precursor frame.

Marriage of Peroxides and Nitrogen Heterocycles: Selective Three-Component Assembly, Peroxide-Preserving Rearrangement, and Stereoelectronic Source of Unusual Stability of Bridged Azaozonides

Stable bridged azaozonides can be selectively assembled via a catalyst-free three-component condensation of 1,5-diketones, hydrogen peroxide, and an NH-group source such as aqueous ammonia or ammonium salts. This procedure is scalable and can produce gram quantities of bicyclic stereochemically rich heterocycles. The new azaozonides are thermally stable and can be stored at room temperature for several months without decomposition and for at least 1 year at -10 °C. The chemical stability of azaozonides was explored for their subsequent selective transformations including the first example of an aminoperoxide rearrangement that preserves the peroxide group. The amino group in aminoperoxides has remarkably low nucleophilicity and does not participate in the usual amine alkylation and acylation reactions. These observations and the 15 pK_a units decrease in basicity in comparison with a typical dialkyl amine are attributed to the strong hyperconjugative n_N→σ*_C-O interaction with the two antiperiplanar C-O bonds. Due to the weakness of the complementary n_O→σ*_C-N donation from the peroxide oxygens (a consequence of "inverse α-effect"), this interaction depletes electron density from the NH moiety, protects it from oxidation, and makes it similar in properties to an amide.