Lewis Basic Salt-Promoted Organosilane Coupling Reactions with Aromatic Electrophiles

Abstract

Lewis basic salts promote benzyltrimethylsilane coupling with (hetero)­aryl nitriles, sulfones, and chlorides as a new route to 1,1-diarylalkanes. This method combines the substrate modularity and selectivity characteristic of cross-coupling with the practicality of a base-promoted protocol. In addition, a Lewis base strategy enables a complementary scope to existing methods, employs stable and easily prepared organosilanes, and achieves selective arylation in the presence of acidic functional groups. The utility of this method is demonstrated by the synthesis of pharmaceutical analogues and its use in multicomponent reactions.

Palladium‐Catalyzed Benzylic Silylation of Diarylmethyl Carbonates with Silylboranes under Base‐Free Conditions

“…The CsF/18‐crown‐6‐promoted allylation and benzylation with allyl bromide and benzyl bromide were possible to afford the allylated 4 and benzylated 5 in 85 and 77 % yields, respectively [16a,b] . The same conditions were applicable to the arylation reaction with phthalonitrile to deliver the corresponding triarylmethane 6 in a good yield [16c] …”

Modularity in the Csp3 Space─Alkyl Germanes as Orthogonal Molecular Handles for Chemoselective Diversification

“…Modular coupling strategies are considered highly attractive owing to the ability to rapidly generate a diverse range of compounds through sequential and chemoselective manipulations . While chemoselective coupling approaches have made great progress in the functionalization of aromatic systems, especially through couplings with poly­(pseudo)-halogenated arenes or through different typical transmetalating groups, modular coupling approaches in the C sp3 space have, by comparison, seen much less development. − This is likely due to the inherently greater challenges in performing C sp3 couplings on the one hand but also likely due to the limitations in reactivity and stability of available alkyl functional groups for derivatizations. For multidimensional modularity to be realized, robust functional groups are needed that allow for their independent and orthogonal functionalization in the presence of each other.…”

“…Alkyl-SiMe 3 on the other hand is rather robust and can be involved in C-C couplings only if positioned α to a stabilizing group, such as an aromatic ring, which impacts the overall accessible diversity (see Figure ). Bis -BPin building blocks allow for deborylative alkylation to alkylated BPin derivatives and rich alkyl BPin derivatizations (such as homologation, halogenation, hydroxylation, amination, arylation, and alkenylation) …”

A Base-Promoted Reductive Coupling Platform for the Divergent Defluorofunctionalization of Trifluoromethylarenes

“…The model defluorosilylation product 37 was first isolated from a reaction conducted in NMP on a 5 mmol scale in 40% yield. From 37 , our recently reported fluoride-promoted protocol for benzylsilane cross-coupling to aryl nitriles can be used to generate defluoroarylation products (Scheme a) . This route provides an alternative to Zhang’s recently developed light-promoted Pd-catalyzed trifluoromethylarene C–F arylation method …”