Reductive coupling of ketones and nitriles at a geometrically constrained silanide
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Updated: Nov 6, 2026

A Two-Step Protocol for Umpolung Functionalization of Ketones Via Enolonium Species
Published on: August 16, 2018
Pamela Adienes Benzan Lantigua1, María L G Sansores-Paredes1,2, Martin Lutz3
1Organic Chemistry and Catalysis, Institute for Sustainable and Circular Chemistry, Faculty of Science, Utrecht University 3584 CG Utrecht The Netherlands m.moret@uu.nl.
Abstract:
While silanides ([R3Si-]) are best known for their nucleophilic reactivity, examples have recently been shown to display biphilic reactivity akin to neutral Si(ii) compounds. In this context, we report on the reactivity of silanide [K(18-crown-6)][tmimSi] (tmimH3 = tris(3-methylindol-2-yl)methane) with carbonyl compounds and nitriles. The unusual reductive cross-coupling of a ketone and a nitrile result in the formation of 5-membered silacycles. The ketone and the nitrile coupling partners are each able to form homocoupling products, but at a slower rate. DFT calculations support an Umpolung mechanism involving initial condensation of the ketone and silanide to form an anionic oxasilirane - an analogue of which can be isolated for benzaldehyde - that readily opens at the Si-C bond to insert a nitrile molecule.
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