Vinyl‐ und Alkinyl‐Azide: altbekannte Intermediate im Fokus moderner Synthesemethoden

Abstract

Auf die Schliche gekommen: Während 1‐Azidoalkene schon lange als wichtige Intermediate zur Bildung von vielen Stickstoffheterocyclen bekannt sind, konnte die Existenz der entsprechenden 1‐Azidoalkine für lange Zeit nicht zweifelsfrei bewiesen werden. Die Synthese von 1‐Azidoacetylen, das zum ersten Mal vollständig charakterisiert wurde, erbrachte erst kürzlich den unumstößlichen Beweis für die Existenz dieser Substanzklasse.

Azide–Enolate Cycloaddition‐Rearrangement Enables Direct α‐Amination of Amides and Enelactam Synthesis from Esters**

“…In combination with our earlier work on N ‐vinyl amides, the reaction pathways uncovered in this study provide a framework for understanding of the reactivity determinants in the wider vinyl azide‐enolate (3+2) cycloaddition‐rearrangement manifold (Scheme 6). [92,93] The lithium enolates of aldehydes, esters, lactone and amides have all been demonstrated to undergo facile (3+2) cycloaddition with substituted vinyl azides, with conserved regiochemistry across all substrate classes. The initial hydroxy triazoline cycloadducts then undergo formal extrusion of nitrogen and rearrangement in a substrate‐dependent manner, in a range of processes governed by the presence or absence of a suitable nucleofuge (OMe), the ability of substituents to migrate through a 1,2 shift (H, N or O) or the possibility of an additional pathway (ene‐γ‐lactam formation) to give the diverse range of products obtained.…”

PhI(OAc)2‐Mediated Radical Trifluoromethylation of Vinyl Azides with Me3SiCF3

“…Vinyl azides have served as versatile materials for the synthesis of various nitrogen‐containing molecules, especially, azaheterocycles 10. Vinyl azides work as a radical acceptor.…”