Copper(II) chloride has some highly specialized applications in the synthesis of organic compounds. It affects the chlorination of aromatic hydrocarbons&mdash;this is often performed in the presence of aluminium oxide. It is able to chlorinate the alpha position of carbonyl compounds:
This reaction is performed in a polar solvent such as dimethylformamide, often in the presence of lithium chloride, which accelerates the reaction.
, in the presence of oxygen, can also oxidize phenols. The major product can be directed to give either a quinone or a coupled product from oxidative dimerization. The latter process provides a high-yield route to 1,1-binaphthol:
Such compounds are intermediates in the synthesis of BINAP and its derivatives.
Copper(II) chloride dihydrate promotes the hydrolysis of acetonides, i.e., for deprotection to regenerate diols or aminoalcohols, as in this example (where TBDPS = tert-butyldiphenylsilyl):
 also catalyses the free radical addition of sulfonyl chlorides to alkenes; the alpha-chlorosulfone may then undergo elimination with a base to give a vinyl sulfone product.