Cobalt-Catalyzed Reductive Carboxylation of α,β-Unsaturated Compounds with Carbon Dioxide

Abstract

The gaseous carbon dioxide incorporation reaction with α,β-unsaturated compounds was examined in the presence of a catalytic amount of bis(acetylacetonato)cobalt(II) and using diethylzinc as a reductant. After screening with various electron-withdrawing groups, both α,β-unsaturated nitriles and carboxamides were found to efficiently capture carbon dioxide to provide the corresponding carboxylates or malonates in good to excellent yields under mild conditions.

Improved Conditions for the Visible-Light Driven Hydrocarboxylation by Rh(I) and Photoredox Dual Catalysts Based on the Mechanistic Analyses

“…The most common strategy to accomplish the hydrocarboxylation is to utilize a metal hydride complex as an active species. However, in these reactions, more than a stoichiometric amount of highly active, metallic reductants such as ZnEt 2 , AlEt 3 , or hydrosilanes are usually required to promote the reduction process in the catalytic cycle (Takaya and Iwasawa, 2008; Williams et al, 2008; Fujihara et al, 2011; Li et al, 2011; Hayashi et al, 2015; Wang et al, 2015; Zhu et al, 2015; Kawashima et al, 2016). In order to realize a more efficient and environmentally-friendly system, the reaction which necessitates just a catalytic amount of metallic reagents is highly desirable.…”

Recent Advances of CO2 Fixation via Asymmetric Catalysis for the Direct Synthesis of Optically Active Small Molecules

“…The [2＋2＋2] cycloaddition product 12 was obtained in good yield with a promising enantioselectivity (20% ee) using catalytic cationic [Rh(cod) 2 ]BF 4 and (S)-H 8 -BINAP. Recently, catalytic hydrocarboxylation of alkenes with CO 2 has been reported using transition-metal-catalyst, such as Ni, [52] Fe, [53] or Co, [54,55] with diethylzinc or ethylmagnesium halides as a hydride source. In 2016, Mikami and co-workers [56] reported a Rh-catalyzed hydrocarboxylation of alkenes with CO 2 .…”

Reductive Carbon–Carbon Bond Forming Reactions with Carbonyls Mediated by Rh–H Complexes

“…The reaction efficiently captured CO 2 to provide the corresponding products under mild condition. [36] Mikami and his group disclosed a remarkably efficient Rh-H complex for reductive α-carboxylation of α, -unsaturated esters and CO 2 . [37] The reaction could apply to asymmetric synthesis of half-ester of dicarboxylic acid by using a chiral [Rh-(S)-SEGPHOS(cod)] complex (Scheme 12).…”