Synthesis of tetrafluoroethylene- and tetrafluoroethyl-containing azides and their 1,3-dipolar cycloaddition as synthetic application

Abstract

Tetrafluoroethylene-containing azides are accessed in two steps (one pot) from tetrafluoroalkyl bromides by metalation and reaction with electrophilic azides. Subsequent copper(i)-catalyzed azide-alkyne cycloaddition afforded N-tetrafluoroethyl and N-tetrafluoroethylene 4-substituted 1,2,3-triazoles. In addition, the protocol for the synthesis of 4,5-disubstituted 1,2,3-triazoles is presented.

Synthesis, Stability and Reactivity of α‐Fluorinated Azidoalkanes

“…Longer-chain azidoperfluoroalkanes wasp repared in an analogousw ay (Scheme 14). [22,23] Azidopentafluoroethane formed using stable pentafluoroethyllithium (Scheme 15), [22] and tetrafluoroethylene-containing azides 6 via organomagnesium compounds generatedb yu sing Turbo-Grignard reagents (Scheme 16). [23]…”

“…Aw ay to circumvent the problemint he synthesis of 4,5-disubstituted 1,2,3-triazoles is to use ac ombination of copper acetylide and iodine, which provides 5-iodo triazoles amenable to Pd-catalyzed cross-couplingr eactions (Scheme 29). [22,23,40] Another pathway to fully substituted triazoles with N-fluoroalkylgroups is the [3+ +2] cycloaddition of azides with carbonyl compounds catalyzed by pyrrolidine or other bases,s uch as 1,8-diazabicyclo[5.4.0]undec-7-ene( DBU, Scheme 30). [21,41] When pyrrolidine is used as ac atalyst, the reaction proceeds via enamines, as verified by ac ontrol experiment in which an isolatede namine afforded with CF 3 N 3 the same triazole product (R 1 = CO 2 Et, R 2 = Me).…”

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, [27] and for stereoselectives ynthesiso f2 ,2-diaryl or 2-alkyl-2-aryl-substituted N-sulfonyl enamides ( Figure 1B). [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.…”

Advances in the Synthesis and Application of Tetrafluoroethylene‐ and 1,1,2,2‐Tetrafluoroethyl‐Containing Compounds

“…The organomagnesium reagents were further studied in the preparation of tetrafluoroethylene‐containing azides 100 by reaction with tosyl azide or nonaflyl azide (Scheme ) . As we recently reported the synthesis of N ‐perfluoroalkyl‐1,2,3‐triazoles via copper(I)‐catalyzed azide–alkyne cycloaddition, the azides were used as an extension to that study with copper(I) 3‐methylsalicylate (CuMeSal) as the catalyst.…”

“…The organomagnesium reagents were further studied in the preparation of tetrafluoroethylene-containing azides 100 by reaction with tosyl azide or nonaflyl azide (Scheme 57). [141] As we recently reported the synthesis of N-perfluoroalkyl-1,2,3-triazoles via copper(I)-catalyzed azide-alkyne cycloaddition, [142] the azides were used as an extension to that study with copper(I) 3-methylsalicylate (CuMeSal) as the catalyst. In addition to a series of 4-substituted 1,2,3-triazoles bearing N-tetrafluoroethylene or N-tetrafluoroethyl groups, two 4,5-disubstituted analogs 102a and 102b were also synthesized.…”