Synthesis of 3‐Aminopiperidines via I(III)‐Mediated Olefin Diamination with (Hetero)aryl Nucleophiles

Abstract

Abstract3‐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.magnified image

A decade of lessons in the activation of ArIL2 species

“…The synthetic route to Weiss' reagent is simple, commercially available PhI(OAc) 2 is reacted with 2 equivalents of TMS-OTf in CH 2 Cl 2 , which was assumed to generate PhI(OTf) 2 (much more on this later), followed by the addition of 2 equivalents of a pyridine or quinoline ligand (Scheme 1). 10,11 The dicationic coordination complex precipitates immediately from solution and can be easily isolated. We obtained a crystal structure of the 4-DMAP and pyridine analogues and later the 4-cyanopyridine analogue.…”