A Novel Rearrangement Reaction of N‐Acyliminium Ions Leading to Heterobicycles Arylated at Bridgehead Atom

Abstract

Starting with thiazolines, an important class of heterocyclic imines, a novel rearrangement reaction of corresponding N‐acyliminium ions is described. Furthermore, a new class of heterobicyclic compounds arylated at a single bridgehead atom is obtained diastereospecifically.

Synthesis of Functionalized Isoindolinones via Calcium Catalyzed Generation and Trapping of N-Acyliminium Ions

“…N -Acyliminium ions represent a highly useful reactive intermediate that has found use in a plethora of synthetic methodologies and total synthesis alike. , Over the course of several decades, these reactive intermediates have been employed to form new carbon–carbon and carbon–heteroatom bonds with great success. In particular, N -acyliminium ions have shown utility in the synthesis of fused ring systems through intramolecular trapping of the generated reactive intermediate. − This strategy has been thoroughly explored over the last two decades with noted examples such as in the total syntheses of stemoamide, crispine A, and minfiensine (Figure ). …”

Scaffold Diversity from N-Acyliminium Ions

“…Only cyclization steps that directly involve NAI intermediates are included in this review. Rearrangement reactions of NAIs leading to cyclized compounds of different scaffolds, NAI cyclizations that lead to a reduced or equivalent count of cyclic systems, and cyclizations involving vinylogous NAIs − are not included herein. NAI chemistry has also been widely applied for the functionalization of monocyclic pyrrolidines and piperidines at the α-position; − however, reactions used for the introduction of substituents on monocyclic scaffolds are also outside the scope of this review.…”