page_title: Juliá–Colonna epoxidation
section_title: Total synthesis of Diltiazem
hierarchical_section_title: Juliá–Colonna epoxidation / Applications to synthesis / Total synthesis of Diltiazem
caption_attribution_description: English: The Juliá-Colonna Epoxidation has been applied to the Total Synthesis of Diltiazem™. From Adger, B. M.; Barkley, J. V.; Bergeron, S.; Cappi, M. W.; Flowerdew, B. E.; Jackson, M. P.; McCague, R.; Nugent, T. C.; Roberts, S. M., Improved procedure for Julia-Colonna asymmetric epoxidation of α,β-unsaturated ketones: total synthesis of diltiazem and Taxol (TM) side-chain. J. Chem. Soc.-Perkin Trans. 1 1997, (23), 3501-3507.
context_page_description: The Juliá–Colonna epoxidation is an asymmetric poly-leucine catalyzed nucleophilic epoxidation of electron deficient olefins in a triphasic system. The reaction was reported by Sebastian Juliá at the Chemical Institute of Sarriá in 1980, with further elaboration by both Juliá and Stefano Colonna.
  In the original triphasic protocol, the chalcone substrate is soluble in the organic phase, generally toluene or carbon tetrachloride. The alkaline hydrogen peroxide oxidant is soluble primarily in the aqueous phase, and the reaction occurs at the insoluble polymer layer at the interface of the two phases. Alternative biphasic and monophasic protocols have been developed with increased substrate accessibility and reaction rate.
  The efficient enantioselective catalytic epoxidation under mild conditions is of great synthetic utility. Not only are epoxides effective synthons for a range of transformations, they have a significant presence in natural products structures. Furthermore, the reaction has been effectively scaled up to industrially useful levels, with work conducted notably by Bayer and Evonik.
context_section_description: Adger et al. utilized the biphasic Juliá–Colonna epoxidation with immobilized poly-L-leucine (I-PLL) and urea hydrogen peroxide (UHP), and 8-diazabicyclo[5.4.0]undec-7-ene (DBU) as the key step in the efficient synthesis of Diltiazem (Figure 6.) Diltiazem is a commercially available pharmaceutical which acts as a calcium channel blocker.
caption: Figure 6: The Juliá–Colonna Epoxidation has been applied to the Total Synthesis of Diltiazem.[11]
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