3-Aminopiperidines are a valuable motif present in small molecule pharmaceuticals and bioactive natural products. Synthesis of these moieties via olefin diamination would be an attractive approach, however significant challenges remain with regards to both regioselectivity and exogenous nucleophile scope. Herein, we report a metal-free olefin diamination via a "heterocyclic group transfer" (HGT) reaction of I(III) N-HVI reagents, giving rise to 3-aminopiperidines with high selectivity. The HGT strategy leverages heteroarenes as oxidatively masked amine nucleophiles, giving rise to (hetero)arylonium salt products which are isolated via simple trituration and provide a versatile handle for downstream diversification. This represents only the second 6-endo selective I(III)-mediated diamination reaction and mechanistic studies indicate ring opening of an intermediate aziridinium ion is responsible for the 6-endo selectivity.
SiCl4 promotes isocyanide additions to oxoalkenenitriles to selectively generate 3-acylpyrroles, 2-aminofurans, or pyrrolidinones. Cyclic oxoalkenenitriles add 2 equiv of an isocyanide that installs the two core atoms of an acylpyrrole and a nitrile substituent, whereas acyclic oxoalkenenitriles add 1 equiv of an isocyanide to afford 2-aminofurans; subsequent air oxidation generates pyrrolidinones via a furan oxygenation-cleavage-cyclization sequence. The syntheses proceed under mild conditions to rapidly access three richly decorated heterocycles.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.