Silver-Catalyzed Regioselective Carbomagnesiation of Alkynes with Alkyl Halides and Grignard Reagents

Abstract

A silver-catalyzed carbomagnesiation of alkynes with alkyl halides and Grignard reagents afforded alkenyl Grignard reagents regioselectively, where the alkyl group of the alkyl halide, but not that of the Grignard reagent, was introduced into the alkyne. Application to δ-haloalkylacetylenes yielded cyclopentanes or a tetrahydrofuran containing an exo-methylene substituent via 5-exo-dig cyclization.

Copper‐Catalyzed Regioselective Hydroalkylation of 1,3‐Dienes with Alkyl Fluorides and Grignard Reagents

“…cupration of the diene with the copper hydride species generated by b-hydrogen elimination of alkyl copper intermediates. [12,13] Al abeling experiment using CD 3 CD 2 MgBr indicated that the KIE of this reaction is 1.6. [14,15] To shed light on the active species of the hydrocupration, we conducted stoichiometric reaction with the copper hydride complex 6 [Eq.…”

“…[12,13] Al abeling experiment using CD 3 CD 2 MgBr indicated that the KIE of this reaction is 1.6. [b] Reaction time was 60 h. cupration of the diene with the copper hydride species generated by b-hydrogen elimination of alkyl copper intermediates.…”

Transition Metal Catalyzed Alkylation at sp3-, sp2-, and sp-Carbons

“…As a more practical and convenient route to 52, we developed the three component coupling reaction of alkynes, alkyl iodides and i BuMgCl catalyzed by AgOTs without necessity of preparing a Grignard reagent prior to the reaction (Scheme 12, route B). 38 As shown in eq. 33, this reaction was complete in 1 h at 10 .…”

“…21). 38 Alkylsilver would be expected to be formed as an active species and to add to the enyne. 39 This catalytic system can also be applied to the alkylation of alkynes (vide infra).…”

Recent advances in transition-metal-catalyzed intermolecular carbomagnesiation and carbozincation

“…Kambe reported a rare example of silver catalysis for carbomagnesiation reactions of simple terminal alkynes (Scheme 39) [121–122]. They proposed that the catalytic cycle (Scheme 40) would be triggered by the transmetalation of AgOTs with iBuMgCl to afford isobutylsilver complex 4C .…”