Temperature Dependence of the Reduction of Phthalic Thioanhydrides by NaBH4: Competition between 3??Hydroxythiolactone and Phthalide Formation

…, L Lutsen, D Vanderzande, J Gelan

Index: Polec, Iwona; Lutsen, Laurence; Vanderzande, Dirk; Gelan, Jan European Journal of Organic Chemistry, 2002 , # 6 p. 1033 - 1036

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Citation Number: 6

Abstract

Abstract The reduction of phthalic thioanhydrides with NaBH 4 at between 0 and− 20 C leads to the selective formation of 3-hydroxy-2-thiophthalides, whereas higher temperatures favour the formation of the corresponding phthalide derivatives. A mechanism is proposed that can explain these observations. Kinetic control at low temperatures leads to an improved stability of the intermediate alkoxide, thus allowing isolation of the γ- ...