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Efficient Construction of Drug-like Bispirocyclic Scaffolds Via Organocatalytic Cycloadditions of α-Imino γ-Lactones and Alkylidene Pyrazolones
Published on: February 7, 2019
Cycloheptatriene-Fused Benzosiloles: Synthesis and Reactivity
Kenichi Murai1, Ryuma Ochi2, Mohamed S H Salem3
1School of Pharmaceutical Sciences, Wakayama Medical University, Wakayama 640-8156, Japan.
Abstract:
The synthesis of cycloheptatriene-fused benzosiloles is reported via a rhodium-catalyzed domino cyclopropanation/Büchner ring-expansion sequence of biphenyl-containing silyldiazomethanes. The resulting scaffold exhibits characteristic reactivity arising from a cycloheptatriene-norcaradiene equilibrium, as demonstrated by Diels-Alder trapping experiments. Oxidative conversion of the cycloheptatriene unit further provides a silicon-bridged tropylium cation, representing a cationic analogue of dibenzosilole. These results establish cycloheptatriene-fused benzosiloles as a new class of silacyclic frameworks with distinctive reactivity.
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