| 摘要 |
Stereo and regioselective 1,4- alkanoyloxy halogenation of 1,3 diene is described. The 1,3 diene is converted with an alkali (ne earth) metal haloide opt. with carboxylate in solvent. The solvent is a lower aliphatic, opt. substd. carboxyl acid corresp. to the desired alkanoyloxy group and to the carboxylate ion in the metal carboxylate. Process is carried out in the presence of Pd as a catalyst and oxidn. medium or system. This comprises benzoquinone, carbamide hydroperoxide, hydroquinone oxidising medium, combined with a catalytic quantity of benzoquinone or oxygen in combination with an oxidation catalysing metal ion. The oxidn. catalysing metal ion is Cu(2+) ad CuCl2. The hydroquinone oxidising oxidn. medium is carbamide hydroperoxide or chromium trioxide. The Pd catalyst is palladium acetate present as 5-10 mole% calculated on the 1,3 diene. 1,3 diene can undergo 1,4 acetoxy chlorination with lithium chloride and lithium acetate in acetic acid in the presence of benzoquinone as the oxidising agent, at room temp. (Provisional Basic previously advised in Week 8346) |
