Chemoselective Aza-[4+3]-annulation of N-Perfluoroalkyl-1,2,3-triazoles with 1,3-Dienes: Access to N-Perfluoroalkyl-Substituted Azepines

Abstract

Rhodium-catalyzed transannulation of N-perfluoroalkylated 1,2,3-triazoles with 1,3-dienes under microwave heating proceeded chemoselectively via the formal aza-[4+3]-pathway, affording N-perfluoroalkyl-substituted 2,5dihydroazepines. A unique regioselectivity profile was observed in annulation with 1-substituted 1,3-diene, affording unusual 5,6-disubstituted examples. Transannulation of triazoles with 2-trimethylsilyloxybutadiene provided N-perfluoroalkylsubstituted azepinone derivatives.

Stereoselective Synthesis of (Z)‐β‐Enamido Triflates and Fluorosulfonates from N‐Fluoroalkylated Triazoles

“…They have been used for the preparation of different types of heterocycles, N ‐sulfonyl‐containing compounds, and for stereoselective synthesis of 2,2‐diaryl or 2‐alkyl‐2‐aryl‐ substituted N ‐sulfonyl enamides (Figure B) . We have recently shown that N ‐fluoroalkyl triazoles prepared by a [3+2] cycloaddition of stable and safe azido(per)fluoroalkanes and alkynes are efficiently transformed to new N ‐fluoroalkyl heterocycles via rhodium carbenoids . However, the reactivity profiles of N ‐fluoroalkyl triazoles and N ‐sulfonyl triazoles are markedly different.…”

“…[28][29][30][31][32][33] We have recently shown that N-fluoroalkyl triazoles prepared by a[ 3 + +2] cycloaddition of stable and safe azido(per)fluoroalkanes anda lkynes [34][35][36] are efficiently transformed to new N-fluoroalkyl heterocycles via rhodiumc arbenoids. [37,38] However,t he reactivity profiles of Nfluoroalkyl triazoles and N-sulfonyl triazoles are markedlyd ifferent.…”

Synthesis, Stability and Reactivity of α‐Fluorinated Azidoalkanes

“…They are also compounds of broad synthetic utility.I nt he presence of aR h II catalystu nder microwaveh eating, triazoles 11 eliminate nitrogen and form rhodiumc arbenoids, which undergo av ariety of transannulation reactions giving nitrogen heterocycles, such as N-fluoroalkyl pyrroles, imidazoles, azepines and other. [36,37] In the presence of triflic acid at room temperature, b-enamido triflates form from triazoles 11. [38] Click reactionb etween amides of azidodifluoroacetic acid and N-propargylated amides of protected amino acids gives pseudotetrapeptides with ar igid triazole core (Scheme 28).…”

“…They are also compounds of broad synthetic utility. In the presence of a Rh II catalyst under microwave heating, triazoles 11 eliminate nitrogen and form rhodium carbenoids, which undergo a variety of transannulation reactions giving nitrogen heterocycles, such as N‐fluoroalkyl pyrroles, imidazoles, azepines and other . In the presence of triflic acid at room temperature, β‐enamido triflates form from triazoles 11 …”

Recent Advances in Transition-Metal-Catalyzed (4+3)-Cycloadditions

“…In a single example using diene 2.10d (Scheme 2.10), it was possible to generate azepinones 2.10e as the (4+3)-cycloadduct. 27…”