Experimental and Computational Studies on Cobalt(I)-Catalyzed Regioselective Allylic Alkylation Reactions |
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| Authors: | Philip Andreetta Dr. Robert T. Martin Charafa Souilah Dr. Ángel Rentería-Gómez Dr. Zhihui Song Yas Khorramshahi Bayat Dr. Sergei Ivlev Prof. Dr. Osvaldo Gutierrez Prof. Dr. Alicia Casitas |
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| Affiliation: | 1. Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, 35043 Marburg, Germany;2. Department of Chemistry and Biochemistry, University of Maryland, College Park. 8051 Regents Dr, College Park, Maryland, 20742 USA;3. Department of Chemistry, Texas A&M University, College Station, Texas, 77843 USA |
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| Abstract: | Here, we report the development of cobalt(I)-catalyzed regioselective allylic alkylation reactions of tertiary allyl carbonates with 1,3-dicarbonyl compounds. A family of well-defined tetrahedral cobalt(I) complexes bearing commercially available bidentate bis(phosphine) ligands [(P,P)Co(PPh3)Cl] are synthesized and explored as catalysts in allylic alkylation reactions. The catalyst [(dppp)Co(PPh3)Cl] (dppp=1,3-Bis(diphenylphosphino)propane) enables the alkylation of a large variety of tertiary allyl carbonates with high yields and excellent regioselectivity for the branched product. Remarkably, this methodology is selective for the activation of tertiary allyl carbonates even in the presence of secondary allyl carbonates. This contrasts with the selectivity observed in cobalt-catalyzed allylic alkylations enabled by visible light photocatalysis. Mechanistic insights by means of experimental and computational investigations support a Co(I)/Co(III) catalytic cycle. |
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| Keywords: | Allylic Alkylation Reaction Cobalt Catalysis Coordination Cobalt(I) Complexes Reaction Mechanism Theoretical Calculations |
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