Synthesis of Substituted Benzoxacycles via a Pd(II)-Catalyzed Intramolecular Arylation Reaction of Allylic Alcohols

Theoretical investigation into the influence of molar ratio on mixture system: α, γ, δ-HMX molecules coexisting with β-HMX crystal

Molecular dynamics (MD) simulation was conducted to research the effect of molar ratios for α/β-HMX, γ/β-HMX, and δ/β-HMX(octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) mixture systems on thermal stability, sensitivity, and mechanical properties of explosives, and the computing models were established by Materials Studio (MS). The binding energies, the maximum trigger bond length (L_N-NO2), cohesive energy density as well as mechanical properties of the mixture systems and the pure β-HMX crystal were obtained and contrasted. The results demonstrate that the molar ratios have great influence on the binding capacity of molecules between α, γ, δ-HMX, and β-HMX in the mixture systems. The binding energies decrease with the increase of molecular molar ratio and have the maximum values at the 1:1 M ratio. The maximum trigger bond length does not change apparently after mixing, while the cohesive energy density (CED) increases as the molar ratio increases but are all smaller than the pure β-HMX crystal, demonstrating that the sensitivity of the mixture systems increases. The mechanical properties decrease after mixture, which illustrates that the mechanical properties of the pure crystal are superior to the mixture systems.

Acid-catalyzed chirality-transferring intramolecular Friedel–Crafts cyclization of α-hydroxy-α-alkenylsilanes

Acid-catalyzed intramolecular Friedel–Crafts cyclization of optically active α-hydroxy-α-alkenylsilanes possessing a benzene ring (>99% ee) with TMSOTf as a Lewis acid gave enantio-enriched tetrahydronaphthalenes (up to 98% ee).

Stereocontrolled Construction of 1-Vinylindanes via Intramolecular Cyclization of o-Cinnamyl Chalcones

In this paper, a concise route for the synthesis of 1-vinylindanes is described, including (i) NaBH₄-mediated reduction of o-cinnamyl chalcones and (ii) sequential BF₃·OEt₂-mediated intramolecular annulation of the resulting alkenols. The plausible mechanism is proposed and discussed herein. This protocol provides highly effective stereocontrolled cinnamyl-enone cross-coupling to construct three contiguous trans- trans stereocenters and one ( E)-configured alkenyl or styryl group.