Halides perchloric acid esters

THF is useful in the malonic ester synthesis since it dissolves many sodio derivatives. Use of aqueous THF facilitates diazotization of salts of aminopolyphenyls which are sparingly soluble in water and is recommended also for the Schiemann reaction. It is superior to ether as solvent for coupling of an acetylenic Grignard reagent with a propargylic halide. Cremlyn and Chisholm found THF superior to dioxane or Cellosolve as solvent for the hydrogenation of cholesterol at ordinary temperature and pressure with perchloric acid as catalyst. 

The reaction between acyl halides and alcohols or phenols is the best general method for the preparation of carboxylic esters. It is believed to proceed by a Sn2 mechanism.As with 16-57, the mechanism can be S l or tetrahedral. ° Pyridine catalyzes the reaction by the nucleophilic catalysis route (see 16-58). Lewis acids such as lithium perchlorate can be used. 

Chromic anhydride-pyridine, 70 Chromium hexacarbonyl, 71 Chromones, 423 Chromous chloride, 73 Chrysanthemic acid, 49, 50, 207-208 Chrysanthemic esters, 183-184 Cinnamic esters, 362 CitroneUol, 5, 308, 309 Claisen rearrangement, 2, 372 Clemmensen reduction, 426 Cocaine, 384 Codeine, 236, 347, 348 Conjugate addition, 86, 102, 119-120, 133, 226-227, 253, 353, 400 Cope rearrangement, 66, 397 Copper, 73-74 Copper(I) acetate, 80 Copper(II) acetate, 39, 117, 126, 186 Copper(I) bromide-Lithium trimethoxy-aluminum hydride, 80 Copper(I) bromide, 79-80 Copper(I) chloride, 50, 80-81 Copper(II) chloride, 126, 79 Copper(l) cyanoacetate, 74 Copper halide nitrosyls, 73 CopperO) iodide, 81-82 Copper(I) methyltrialkylborates, 4,75 CopperGD perchlorate. 79 COpper(I) phenylacetylide, 237 Copper(II) sulfate, 117 CopperO) trifluoiomethanesulfonate, 75-76... 

---