Cyclisation of UnsaturatedN-Chloroamines under Acidic Conditions: A Polar Reaction via Chloronium Ions

Abstract

Unsaturated N-chloroamines cyclise under acidic conditions without addition of a starter for a radical reaction. Therefore it can be concluded that, under the conditions published to date in the literature, the reaction at least partially proceeds via a polar reaction mechanism rather than via free radicals.

Photochemical Aminochlorination of Alkenes without the Use of an External Catalyst

“…Over the last years, the aminohalogenation reactions became a widespread concern among the researchers worldwide, who were basically focused in improving the stereo‐ and regioselectivity of the reaction. Göttlich pioneered the field through a series of elegant contributions, reporting the addition of N‐ chloroamines to olefins in the presence of copper [4] or palladium catalysts, [5] Lewis acids [6] or tertiary amine salts [7] . Following this idea, Jiang's group reported the first palladium dehydrogenative aminohalogenation of alkenes [8] …”

Synthesis of 3-chloropiperidines by iodide-mediated electrolysis

“…9 We therefore took great interest in finding efficient synthetic methods for the 3-chloropiperidine moiety so that a large variety of derivatives can be screened for their pharmacological properties. Conventional synthetic methods have already been developed in the past (Scheme 1), commonly utilizing oxidants in stoichiometric quantity to chlorinate an unsaturated amine followed by cyclization via a strong acid, 10 transition metal catalysis [11][12][13][14] or iodide catalysis. 15,16 The cyclization via free radicals has been reported as well.…”