Indium triflate: a mild Lewis acid catalyst for thioacetalization and transthioacetalization

Protection of a variety of carbonyl compounds as thioacetals using indium triflate, a mild Lewis acid catalyst, was achieved at ambient temperature in very good yield. Transthioacetalization of oxyacetals into thioacetals was also achieved in an excellent yield. A mixture of carbonyl compound and its respective oxyacetal was also completely converted into thioacetal in the presence of indium triflate. (C) 2002 Elsevier Science Ltd. All rights reserved.