Organic Letters 2014-07-03

Redox-neutral α-sulfenylation of secondary amines: ring-fused N,S-acetals.

Claire L Jarvis, Matthew T Richers, Martin Breugst, K N Houk, Daniel Seidel

Index: Org. Lett. 16(13) , 3556-9, (2014)

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Abstract

Secondary amines react with thiosalicylaldehydes in the presence of catalytic amounts of acetic acid to generate ring-fused N,S-acetals in redox-neutral fashion. A broad range of amines undergo α-sulfenylation, including challenging substrates such morpholine, thiomorpholine, and piperazines. Computational studies employing density functional theory indicate that acetic acid reduces the energy barriers of two separate steps, both of which involve proton transfer.