Synthesis of a New Fluoro-Wang Resin for Solid-Phase Reaction Monitoring by ¹⁹F NMR Spectroscopy

Abstract

A new fluoro-Wang resin is presented which facilitates solid-phase reaction monitoring using 19F NMR. The resin is easily synthesized and amenable to scale-up. The method described herein compliments single-bead FT-IR and 13C NMR techniques. This method allows monitoring of solid-phase reactions even if the resin bound intermediate is unstable to the cleavage conditions. In addition, this is a useful tool to study reaction kinetics on the solid phase.

Structural characterization and quantitation of compound loading of disubstituted benzoates bound to Wang resin through high‐resolution magic angle spinning NMR spectroscopy

“…Any premature cleavage of molecules during the synthesis is easily detected by the occurrence of the methylene signal a, which belongs to the Wang linker of the free resin. It should be mentioned that other protocols for quantifying compound loading for resins containing the Wang linker, based on 13 C or 19 F NMR spectroscopy, 24,25 have been reported. However, these methods require long measurement times or the presence of a fluorine atom.…”

Wittig- and Horner–Wadsworth–Emmons-Olefination Reactions with Stabilised and Semi-Stabilised Phosphoranes and Phosphonates under Non-Classical Conditions

“…85 In recent years, research on polymer bound HWE reagents has intensified. [87][88][89][90][91][92][93][94] Salvino et al 90 utilised a Wang resin 41 to bind the HWE reagent (Scheme 11). Wipf 91 used the Wang resin bound HWE reagents to prepare peptide mimetics with an alkeneamide unit within the peptide chain by reacting the polymer bound HWE reagents to N-protected aziridine-carbaldehyde.…”

Monitoring Reactions on Solid Phases with Raman Spectroscopy

“…[12][13][14] Especially for the latter purposes, monitoring of the reaction and identification of the target compounds on solid supports is of major importance.T he traditionallyu sed procedures for the identification of compounds, such as elemental analysisa nd cleavage, cause drawbacks in solid-phase chemistry duet ot he loss of material and are nowadays replaced or supplemented by new techniques for the on-beada nalysiso fr eactions. The most important methods, which offer severala dvantages such as non-destructive analysis, have been introduced with the development of gelphase NMR analysis, [15,16] the use of the magic-angle spinning technique [17,18] and 19 FNMR monitoring of reactions through introduction of fluorine linkers. [19,20] IR and Raman measurements, both of which offer the advantageofvery fast measurements, have also been used for monitoring reactionso np olymeric material.…”

“…The most important methods, which offer severala dvantages such as non-destructive analysis, have been introduced with the development of gelphase NMR analysis, [15,16] the use of the magic-angle spinning technique [17,18] and 19 FNMR monitoring of reactions through introduction of fluorine linkers. [19,20] IR and Raman measurements, both of which offer the advantageofvery fast measurements, have also been used for monitoring reactionso np olymeric material. [21][22][23][24] Whereas IR analysish as already found its way into standard proceduresf or monitorings olid-phase reactions [25][26][27] and, in selected examples,t he progress of the reaction, [27][28][29][30][31] Raman and surface-enhanced Raman spectroscopy has been reported only in af ew applicationsf or the identification of smallc ompounds on solid phases,p robablyd ue to the limiteda vailability of Raman instruments.…”