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Synthesis of a Borylated Ibuprofen Derivative Through Suzuki Cross-Coupling and Alkene Boracarboxylation Reactions
Published on: November 30, 2022
Linear Cu(i) chalcogenones: synthesis and application in borylation of unsymmetrical alkynes
Katam Srinivas1, Chatla Naga Babu, Ganesan Prabusankar
1Department of Chemistry, Indian Institute of Technology Hyderabad, ODF Campus, Yeddumailaram, Telangana 502 205, India. prabu@iith.ac.in.
Abstract:
The syntheses and structures of copper(i) chalcogenone complexes are described. The homoleptic mononuclear copper(i) complexes [(IPr[double bond, length as m-dash]E)2Cu]ClO4, IPr[double bond, length as m-dash]E, 1,3-bis(2,6-diisopropylphenyl)imidazoline-2-thione (1) and 1,3-bis(2,6-diisopropylphenyl)imidazoline-2-selone (2); [(IMes[double bond, length as m-dash]E)2Cu]ClO4, IMes[double bond, length as m-dash]E, 1,3-bis(2,4,6-trimethylphenyl)imidazole-2-thione (3) and 1,3-bis(2,4,6-trimethylphenyl)imidazole-2-selone (4); [(IPr[double bond, length as m-dash]E)2Cu]BF4, E = S (5); E = Se (6) and [(IMes[double bond, length as m-dash]E)2Cu]BF4, E = S (7); E = Se (8) are formed from the reduction of copper(ii) to copper(i) with the corresponding imidazoline-2-chalcogenones. X-ray structure analyses of seven compounds (1-3 and 5-8) show that the copper(i) ion is in a perfect linear coordination, while 4 is in quasi-linear geometry. Molecules 2, 4, 6 and 8 are the first structurally characterized homoleptic copper(i) selone complexes. The optical and thermal properties of imidazoline-2-chalcogenones and their copper(i) derivatives are investigated. These complexes are able to act as catalysts in regioselective borylation of numerous unsymmetrical alkynes, yielding synthetically useful vinylboronates. Among catalysts 1-8, catalyst 4 is highly selective towards the regioselective boron addition of 1-phenyl-1-propyne.
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