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2,2,6,6-Tetramethylpiperidin-1-yloxycarbonyl: A Protecting Group for Primary, Secondary, and Heterocyclic Amines

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posted on 2018-10-17, 13:03 authored by Joseph R. Lizza, Maximilian Bremerich, Stephanie R. McCabe, Peter Wipf
The 2,2,6,6-tetramethylpiperidin-1-yloxycarbonyl (Tempoc) protecting group is readily introduced by the reaction of amines with a new acyl transfer reagent, 4-nitrophenyl (2,2,6,6-tetramethylpiperidin-1-yl) carbonate (NPTC). Tempoc has a reactivity profile that complements the commonly used t-butyloxycarbonyl (Boc) and benzyloxycarbonyl (Cbz) protecting groups. Deprotection can be achieved under mild reductive conditions with in situ generated Cu­(I) species or by thermolytic cleavage at 135 °C. Mechanistic studies on the deprotection of Tempoc-indole suggest a combination of ionic and radical fragmentation pathways under thermal conditions.

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