Nickel-catalyzed Suzuki Coupling of Cycloalkyl Silyl Peroxides with Boronic Acids

Abstract

A nickel-catalyzed Suzuki alkyl-aryl coupling of cycloalkyl silyl peroxides with boronic acids is reported. The primary and secondary ketoalkyl electrophiles generated through C–C bond cleavage were amenable, providing rapid access to a variety of distal arylated alkyl ketones. A radical pathway is proposed for this reaction.

Nickel-Catalyzed Allylic Defluorinative Cross-Electrophile Coupling with Cycloalkyl Silyl Peroxides as the Alkyl Source

“…Ring opening reactions involving C–C bond cleavage provide unique reaction pathways in organic synthesis to utilize diverse cyclic substrates with skeletal transformations. , However, the majority of these reactions rely on the use of strained small carbocycles as precursors. Notably, unstrained cycloalkyl silyl peroxides (CSP) have been recently employed as carbonyl-containing alkyl sources via alkoxy-radical initiated C–C bond scissoring in various transition metal-catalyzed reactions under redox-neutral conditions (Scheme A). − The pioneering work of Maruoka et al enables N -alkylation of amides or anilines using CSP as alkylating agents under copper catalysis. , Later on, the scope of nucleophiles for the reactions with CSP has been extended to diboronate, silyl boronate, terminal alkynes, aryl boronic acids, , carboxylic acids, , and amide-directed arenes by the use of copper, iron, or nickel catalysis (Scheme A, eq 1). Very recently, Maruoka and co-workers applied CSP as the alkyl source in copper-catalyzed aryl-alkylation of styrenes (Scheme A, eq 2) .…”

“…3−10 The pioneering work of Maruoka et al enables N-alkylation of amides or anilines using CSP as alkylating agents under copper catalysis. 3,4 Later on, the scope of nucleophiles for the reactions with CSP has been extended to diboronate, 5 silyl boronate, 5 terminal alkynes, 6 aryl boronic acids, 7,8 carboxylic acids, 4,9 and amide-directed arenes 10 by the use of copper, iron, or nickel catalysis (Scheme 1A, eq 1). Very recently, Maruoka and co-workers applied CSP as the alkyl source in copper-catalyzed aryl-alkylation of styrenes (Scheme 1A, eq 2).…”

The Formation of C–C or C–N Bonds via the Copper-Catalyzed Coupling of Alkylsilyl Peroxides and Organosilicon Compounds: A Route to Perfluoroalkylation

“…However, despite its long history, radical chemistry remains relatively underdeveloped. Recently, we have reported a series of radical-mediated synthetic transformations based on the homolytic cleavage of alkylsilyl peroxides catalyzed by copper, − nickel, and iron , salts. These synthetic transformations allowed the facile amidation, amination, acyloxylation, borylation, silylation, alkylation, ,, arylation, , and alkynylation of intermediary carbon radicals generated in situ from alkylsilyl peroxides.…”

“…Recently, we have reported a series of radical-mediated synthetic transformations based on the homolytic cleavage of alkylsilyl peroxides catalyzed by copper, − nickel, and iron , salts. These synthetic transformations allowed the facile amidation, amination, acyloxylation, borylation, silylation, alkylation, ,, arylation, , and alkynylation of intermediary carbon radicals generated in situ from alkylsilyl peroxides. In addition to these synthetic transformations, the development of simple yet useful functional group transformations for in situ generated radical species is also an important issue in this field .…”

Cu-Catalyzed Enantioselective Alkylarylation of Vinylarenes Enabled by Chiral Binaphthyl–BOX Hybrid Ligands

“…We recently reported Cu-catalyzed C­(sp 3 )–C­(sp 2 ) bond formations using alkylsilyl peroxides (ASPs), which are bench-stable and easy-to-handle alkyl radical precursors, and arylboronic acids via a radical process . On the basis of that study, we hypothesized that the generation of alkyl radicals ( INT-1 ) from ASPs and a Cu I catalyst in the presence of vinylarenes could give the corresponding benzyl radicals ( INT-2 ).…”