277-Thiopyrans, electroreductions

Electroreductions of 2//-thiopyrans 13a and 13b each afforded an equimolar mixture of isomeric dihydrothiopyrans 14a and 14b (Scheme 4) (97MI2). Although the products were not separated, no 13a 13b or 14a 14b interconversion was... 

The presence of an electron-withdrawing substituent can favor reductions of heterocycles. In this way, the electroreduction of an activated thiopyran affords a dihy-drothiopyran with elimination of dimethy-lamine (Scheme 14) [19]. 

Functionalized dihydrothiopyran derivatives can be obtained by electroreduction of triactivated [19] (vide supra Scheme 14) and tetraactivated 4//-thiopyrans [261]. 

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