Silasubstitution of bioactive molecules has been regarded as a useful and efficient strategy for the development of new drugs. From a drug discovery viewpoint, investigations of sila(benzo)suberones are of great significance and in great demand. However, sila(benzo)suberones are surprisingly under-represented to date because of the lack of methodology to incorporate the silicon element into (benzo)suberones.
Could the C-C δ-bond of cyclopropenones and the C-Si δ-bond of (benzo)silacyclobutanes be efficiently cleaved simultaneously, and subsequently exchanged by treatment with a proper transition-metal catalyst? This approach would constitute an unprecedented route to the synthesis of diverse sila-(benzo)suberones. Research fellow Zhao’s group reported a novel ring-expansion method to join cyclopropenones with (benzo)silacyclobutanes, thus directly constructing sila-(benzo)suberones under mild reaction conditions in the internationally well-known chemistry journal-Angew. Chem. Int. Ed.
Firstly, the silacyclobutane was treated with Ni(cod)2 and the cyclopropenone in the case of the Pd(OAc)2 catalyst. Then, the scope with respect to the cyclopropenone compounds was investigated. Finally they examined the scope with respect to the cyclopropenones under the modified reaction conditions. Various diarylcyclopropenones bearing substituents at either the para- or meta-position of the appended aryl group proceeded smoothly to afford the desired silabenzosuberones in satisfactory yields.
In summary, their group developed the first intermolecular δ-bond cross-exchange reaction between the C-C bond of cyclopropenones and C-Si bond of (benzo)silacyclobutanes. This reaction constitutes an unprecedented route for the synthesis of various sila-(benzo)suberones. And it is also the first example of a δ-bond exchange reaction involving cyclopropenones.
The first author of this work is PhD. candidate Wen-Tao Zhao.
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