Copper-Catalyzed Silylperoxidation Reaction of α,β-Unsaturated Ketones, Esters, Amides, and Conjugated Enynes

Abstract

A synthetic method of copper-catalyzed silylperoxidation of α,β-unsaturated carbonyl compounds and conjugated enynes has been developed. The realization of silylperoxidation of the carbon− carbon double bond permits direct access to silicon-containing peroxy products in moderate to good yields. Furthermore, this protocol distinguishes itself by operational simplicity and exhibiting good tolerance of a wide scope of functional groups. This strategy provides an efficient approach to the 1,2-difunctionalization of α,β-unsaturated carbonyl compounds and conjugated enynes.

Recent advances in Cu-catalyzed C(sp3)–Si and C(sp3)–B bond formation

“…A few years later, similar types of reactions were carried out by Loh and co-workers [63]. In this case, a variety of α,β-unsaturated compounds, that, rather than undergoing intramolecular cyclization, could be intercepted at the intermediate radical stage (149) with radical initiator TBHP present in excess, leading to silylated peroxy products 151-156.…”

Copper-catalyzed functionalization of enynes

“…In 2017, Loh, Xu and co-workers 35 disclosed a ligand-free copper-catalyzed regioselective 1,2-silylperoxidation of 1,3enynes 1 using tert-butyl hydroperoxide (TBHP) and triethylsilane (Scheme 18A). Aryl, alkyl, and silyl-substituted 1,3-enynes were both compatible with the process and gave moderate yields of 1,2-functionalized products 30 (Scheme 18B).…”

Copper-Catalyzed Ring-Opening Defluorinative Alkylation of Siloxydifluorocyclopropanes: Synthesis of γ-Fluoro-δ-Ketoesters and γ,δ-Diketonitriles

“…Owing to the necessity of Et 3 N for the smooth transformation, Et 3 N is suggested here to be the H-donor though solvent THF cannot be excluded. On the other hand, intramolecular C−N oxidative coupling of radical B derived from α-bromoamide 5 occurs under the catalysis of Cu II in the presence of a base to furnish lactam D via C. 16 Then, the defluorination of D gave iminium cation E, which undergoes sequential hydrolysis, ring opening, and dehydration to afford γ,δ-diketonitrile 6 as the final product (from E to 6 via F and G). Note that intermediate F was isolated as the product 7 in 30% yield when N-methyl amide 5b was used.…”