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A Lewis acid-surfactant-combined copper bis(dodecyl sulfate) [Cu(DS) 2 ] catalyst served as an efficient and reusable catalyst for the thioacetalization and transthioacetalization of carbonyl compounds and O,O-acetals in water at room temperature. Some of the major advantages of this procedure are high chemoselectivity, ease of operation and purification without any organic solvent, and high yields.

Transesterification Catalyzed by Iron(III) β-Diketonate Species. -The reaction is applied to a wide range of carboxylic esters and alcohols tolerating many functional groups.Benzyl thiol as a nucleophile requires 2 equiv. to form the thioester in high yield [cf. (V)]. Benzyl amine can be applied as a nucleophile as well [cf. (VII)]. Anhydride (XV) proves to be one of the most reactive species. In some cases, similar yields are observed in the absence of Na

Chemoselective (Trans)thioacetalization of Carbonyl Compounds with a Reusable Lewis Acid-Surfactant-Combined Copper Bis(dodecyl sulfate) Catalyst inWater. -A broad spectrum of aldehyde and ketone substrates can be used and many functionalities are tolerated. The process is chemoselective and high yields are obtained in most cases. For the steroid (XIX), however, the process is found to be inferior to known methods. The catalyst can be recovered by centrifugation and reused at least 3 times without loss of activity.