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1.3.1.2 Two-Phase Conditions

DOI: 10.1055/sos-SD-201-00050

Colonna, S.; Perdicchia, D.Science of Synthesis: Stereoselective Synthesis, (20111128.

A significant advance for the JuliàColonna reaction occurred when it was found that the reaction can be performed in nonaqueous conditions by using the solid ureahydrogen peroxide complex as the oxidant in an organic solvent such as tetrahydrofuran containing an organic base such as 1,8-diazabicyclo[5.4.0]undec-7-ene and polymer-supported poly(l-leucine) as the catalyst. In comparison with three-phase conditions, the rate of epoxidation of the model substrate (E)-1,3-diphenylprop-2-en-1-one (8) is increased by two orders of magnitude, and a wider range of substituted enones are capable of reacting.[‌20‌] Moreover, most alkyl groups are tolerated at the β-position or next to the ketone moiety, allowing regioselective oxidations of selected trienediones and highly functionalized enones (Scheme 8).[‌21‌,‌22‌]

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