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A Dinickel Catalyzed Cyclopropanation without the Formation of a Metal Carbene Intermediate.

ABSTRACT: (NDI)Ni₂ catalysts (NDI=naphthyridine-diimine) promote cyclopropanation reactions of 1,3-dienes using (Me₃ Si)CHN₂ . Mechanistic studies reveal that a metal carbene intermediate is not part of the catalytic cycle. The (NDI)Ni₂ (CHSiMe₃ ) complex was independently synthesized and found to be unreactive toward dienes. Based on DFT models, we propose an alternative mechanism that begins with a Ni₂ -mediated coupling of (Me₃ Si)CHN₂ and the diene. N₂ extrusion followed by radical C-C bond formation generates the cyclopropane product. This model reproduces the experimentally observed regioselectivity and diastereoselectivity of the reaction.

SUBMITTER: Maity AK

PROVIDER: S-EPMC8086810 | biostudies-literature | 2021 Jan

REPOSITORIES: biostudies-literature

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A Dinickel Catalyzed Cyclopropanation without the Formation of a Metal Carbene Intermediate.

Maity Arnab K AK Kalb Annah E AE Zeller Matthias M Uyeda Christopher C

Angewandte Chemie (International ed. in English) 20201123 4

(NDI)Ni2 catalysts (NDI=naphthyridine-diimine) promote cyclopropanation reactions of 1,3-dienes using (Me3 Si)CHN2 . Mechanistic studies reveal that a metal carbene intermediate is not part of the catalytic cycle. The (NDI)Ni2 (CHSiMe3 ) complex was independently synthesized and found to be unreactive toward dienes. Based on DFT models, we propose an alternative mechanism that begins with a Ni2 -mediated coupling of (Me3</sub ...[more]

PMID: 33045127

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