Highly Selective Monoalkylation of Active Methylene and Related Derivatives using Alkylsilyl Peroxides by a Catalytic CuI‐DMAP System

Abstract

A new approach for highly selective monoalkylation of active methylene and related derivatives using various types of alkylsilyl peroxides in the presence of copper catalysts under mild conditions has been developed to a synthetically useful level. This approach has a wide substrate scope in terms of both active methylene compounds and alkylsilyl peroxides. In addition, nitroalkanes can also be employed for a copper‐catalyzed selective monoalkylation with alkylsilyl peroxides. The participation of radical species was proposed in the present monoalkylation reactions by the mechanistic study.

Fe-Catalyzed Three-Component Coupling Reaction of α,β,γ,δ-Unsaturated Carbonyl Compounds and Conjugate Dienes with Alkylsilyl Peroxides and Nucleophiles

“…Initially, we investigated the reaction of an α,β,γ,δ-unsaturated carbonyl compound with an alkylsilyl peroxide as a source of alkyl radicals based on our previously reported coupling reaction using alkylsilyl peroxides . Thus, we performed the three-component coupling reaction of ( E )-6-methylhepta-3,5-dien-2-one ( 10a ) with an alkylsilyl peroxide, namely, 11a , and excess MeOH (5 equiv) in dioxane in the presence of 5 mol% of CuOTf or Cu­(OTf) 2 at room temperature for 4 h, which did not furnish any of the desired coupling products (entries 1 and 2 in Table ).…”

“…On the basis of our previous observation, our proposed catalytic mechanism for the three-component coupling reaction of α,β,γ,δ-unsaturated carbonyl compounds with alkylsilyl peroxides and ROH in the presence of catalytic Fe­(OTf) 2 is shown in Scheme . Alkylsilyl peroxide 11 should decompose in the presence of Fe­(OTf) 2 species, leading to the generation of alkoxy radical 32 and iron–silanoxide complex 33 .…”

Fe-Catalyzed Dicarbofunctionalization of Vinylarenes with Alkylsilyl Peroxides and β-Keto Carbonyl Substrates

“…Initially, we investigated the coupling reaction of a vinylarene with an alkylsilyl peroxide, which acts as a source of alkyl radicals, based on our previously reported three-component coupling reaction using alkylsilyl peroxides. , Thus, we carried out the three-component coupling reaction of 4-methoxystyrene 1a with an alkylsilyl peroxide 3a and methyl acetoacetate 4a in the presence of catalytic FeCl 2 or Fe­(OAc) 2 in dioxane at 40 °C for 12 h, which did not furnish the desired three-component coupling product 5a (Table , entries 1 and 2). In contrast, the use of 5 mol % of Fe­(OTf) 2 under similar reaction conditions afforded the desired product 5a in 78% yield (entry 3).…”