Highly Regioselective Radical Amination of Allenes: Direct Synthesis of Allenamides and Tetrasubstituted Alkenes

Abstract

The first controllable, regioselective radical amination of allenes with N-fluoroarylsulfonimide is described to proceed under very mild reaction conditions. With this methodology, a general and straightforward route for the synthesis of both allenamides and fluorinated tetrasubstituted alkenes was realized from a wide range of terminal and internal allenes.

Copper-catalyzed aminooxygenation of styrenes with N-fluorobenzenesulfonimide and N-hydroxyphthalimide derivatives

“…Based on these experimental results and our previous investigations [ 42 – 46 48 ], a plausible mechanism for the copper-catalyzed three-component aminooxygenation of styrenes with NFSI an NHPI is shown in Scheme 2 . Initially, the oxidation of Cu(I) with NFSI provided F–Cu(III)–N complex I , which could transform into a copper(II)-stabilized benzenesulfonimide radical II through a redox isomerization equilibrium.…”

“…We are highly interested in the multiple reaction modes of NFSI [ 37 – 41 ], especially as a nitrogen-centred radical. In this context, we have realized copper-catalyzed benzylic sp 3 C–H amination [ 42 ], aminative multiple functionalization of alkynes [ 43 ], diamination, aminocyanation [ 44 ] and aminofluorination of alkenes [ 45 ], as well as amination of allenes [ 46 ]. Encouraged by these results, we try to develop copper-catalyzed aminooxygenation of alkenes by using NFSI.…”

Monofluoralkenylierung von Dimethylaminoverbindungen durch Radikal‐Radikal‐Kreuzkupplung

“…Sowohl elektronenschiebende als auch elektronenziehende Gruppen in o-, m-und p-Position des aromatischen Rings zeigten sich kompatibel und lieferten die jeweiligen tetrasubstituierten Alkenylfluoride 4aa-ja in zufriedenstellenden Ausbeuten (bis zu 99 %). [25] [20] Tabelle 2: Anwendungsbreite in Bezug auf die verwendeten tertiären Amine. [a] [a] Ausbeutenanisoliertem Produkt.…”

Synthesis of difluoromethylated allenes through trifunctionalization of 1,3-enynes

“…1b) [41][42][43][44][45] , also as one part of our continuous efforts on functionalization of unsaturated compounds [46][47][48][49] , herein, we report a metal-free consecutive trifunctionalization of 1,3-enynes for the assembly of various difluoromethylated allenyl amines ( Fig. 1c) using NFSI as the fluorination and amination source 41,44,[50][51][52][53][54][55][56][57][58][59] . The synthetic potential of difluoromethylated allenes is demonstrated by transformations to a variety of difluoromethylated compounds 21 .…”