Asymmetric Henry reaction catalysed by L‐proline derivatives in the presence of Cu(OAc)2: isolation and characterization of an in situ formed Cu(II) complex |
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| Authors: | H. Atoholi Sema Ghanashyam Bez Sanjib Karmakar |
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| Affiliation: | 1. Department of Chemistry, North Eastern Hill University, Shillong, India;2. Sophisticated Analytical Instrument Facility, Gauhati University, Guwahati, India |
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| Abstract: | Synthesis of asymmetric β‐nitroalcohols by the Henry reaction is one of the most exploited carbon–carbon bond‐forming reactions owing to the versatility of both functional groups for synthetic manipulation by functional group interconversion. Here we report synthesis of a series of proline‐derived compounds to study their catalytic activities for asymmetric Henry reaction in the presence of Cu(OAc)2.H2O. The proline derivative, 2‐((E)‐(((S)‐1‐benzylpyrrolidinyl)diphenylmethylimino)methyl)phenol 1 showed optimum catalytic activity. The catalytic species Cu(II)–1 complex, formed in situ, was isolated and characterized by various spectroscopic techniques and X‐ray crystallography to show a cis‐N2O2 coordination geometry. Asymmetric β‐nitroalcohols were achieved without the use of added base, unlike most of the reported protocols. Copyright © 2014 John Wiley & Sons, Ltd. |
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| Keywords: | Henry reaction β ‐nitroalcohol asymmetric L‐proline copper(II) acetate |
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