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Mechanistic insights into the S_N2-type reactivity of aryl-Co(iii) masked-carbenes for C-C bond forming transformations.

ABSTRACT: Herein we describe the synthesis and characterization of a family of C-metalated aryl-Co(iii) enolates, which can be considered as masked-carbenes, using diazoacetates as coupling partners. These species have been proved to be necessary intermediates in the C(sp²)-C(sp³) bond forming event to obtain cyclic amides, taming the elusive Co(iii)-carbene species. The scope of diazoacetates has been exhaustively examined, varying the nature of the ester and the ?-substitution, and a clear preference for electron-poor carbene precursors is observed. Exhaustive experimental and theoretical studies indicate that an unprecedented intramolecular S_N2-type process governs the formation of the newly formed C-C bond. Furthermore, the key role of several Lewis acids as carboxylate-activating reagents is further explored by DFT calculations.

SUBMITTER: Planas O

PROVIDER: S-EPMC6050605 | biostudies-literature | 2018 Jul

REPOSITORIES: biostudies-literature

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Mechanistic insights into the SN2-type reactivity of aryl-Co(iii) masked-carbenes for C-C bond forming transformations.

Planas O O Roldán-Gómez S S Martin-Diaconescu V V Luis J M JM Company A A Ribas X X

Chemical science 20180529 26

Herein we describe the synthesis and characterization of a family of C-metalated aryl-Co(iii) enolates, which can be considered as masked-carbenes, using diazoacetates as coupling partners. These species have been proved to be necessary intermediates in the C(sp2)-C(sp3) bond forming event to obtain cyclic amides, taming the elusive Co(iii)-carbene species. The scope of diazoacetates has been exhaustively examined, varying the nature of the ester and the α-substitution, and ...[more]

PMID: 30079183

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