《Nickel-catalyzed anti-Markovnikov hydroarylation of unactivated alkenes with unactivated arenes facilitated by non-covalent interactions》 was published in Nature Chemistry in 2020. These research results belong to Saper, Noam I.; Ohgi, Akito; Small, David W.; Semba, Kazuhiko; Nakao, Yoshiaki; Hartwig, John F.. Safety of Methyltriphenylphosphonium bromide The article mentions the following:
Abstract: Anti-Markovnikov additions to alkenes have been a longstanding goal of catalysis, and anti-Markovnikov addition of arenes to alkenes would produce alkylarenes that are distinct from those formed by acid-catalyzed processes. Existing hydroarylations are either directed or occur with low reactivity and low regioselectivity for the n-alkylarene. Herein, we report the first undirected hydroarylation of unactivated alkenes with unactivated arenes that occurs with high regioselectivity for the anti-Markovnikov product. The reaction occurs with a nickel catalyst ligated by a highly sterically hindered N-heterocyclic carbene. Catalytically relevant arene- and alkene-bound nickel complexes have been characterized, and the rate-limiting step was shown to be reductive elimination to form the C-C bond. D. functional theory calculations, combined with second-generation absolutely localized MO energy decomposition anal., suggest that the difference in activity between catalysts containing large and small carbenes results more from stabilizing intramol. non-covalent interactions in the secondary coordination sphere than from steric hindrance. The first undirected hydroarylation of unactivated alkenes RCH=CHR1 (R = C8H17, cyclohexyl, C(CH3)3, etc.; R1 = H, CH3, C2H5, C3H7) with unactivated arenes R2C6H5 (R2 = 3-CH3, 3,4-(CH3)2, 3,5-(CF3)2, etc.) occurs with high regioselectivity for the anti-Markovnikov product, e.g., I. The reaction occurs with a Ni catalyst ligated by a highly sterically hindered N-heterocyclic carbene (NHC). Catalytically relevant arene- and alkene-bound Ni complexes have been characterized, and the rate-limiting step was shown to be reductive elimination to form the C-C bond. DFT calculations, combined with energy decomposition anal. (EDA), suggest that the difference in activity between catalysts containing large and small carbenes results more from stabilizing intramol., non-covalent interactions in the secondary coordination sphere than from steric hindrance. In addition to this study using Methyltriphenylphosphonium bromide, there are many other studies that have used Methyltriphenylphosphonium bromide(cas: 1779-49-3Safety of Methyltriphenylphosphonium bromide) was used in this study.
Methyltriphenylphosphonium bromide(cas: 1779-49-3) is used for methylenation through the Wittig reaction. It is utilized in the synthesis of an enyne and 9-isopropenyl -phenanthrene by using sodium amide as reagent. Safety of Methyltriphenylphosphonium bromide
Referemce:
Bromide – Wikipedia,
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