TY  - JOUR
AB  - Mild reaction conditions are highly desirable for bio-orthogonal side chain derivatizations of amino acids, peptides or proteins due to the sensitivity of these substrates. Transition metal catalyzed cross-couplings such as Suzuki-Miyaura reactions are highly versatile, but usually require unfavourable reaction conditions, in particular, when applied with aryl bromides. Ligand-free solvent-stabilized Pd-nanoparticles represent an efficient and sustainable alternative to conventional phosphine-based catalysts, because the cross-coupling can be performed at considerably lower temperature. We report on the application of such a highly reactive heterogeneous catalyst for the Suzuki-Miyaura cross-coupling of brominated tryptophan derivatives. The solvent-stabilized Pd-nanoparticles are even more efficient than the literature-known ADHP-Pd precatalyst. Interestingly, the latter also leads to the formation of quasi-homogeneous Pd-nanoparticles as the catalytic species. One advantage of our approach is the compatibility with aqueous and aerobic conditions at near-ambient temperatures and short reaction times of only 2 hours. The influence of different N alpha -protecting groups, boronic acids as well as the impact of different amino acid side chains in bromotryptophan-containing peptides has been studied. Notably, a surprising acceleration of the catalysis was observed when palladium-coordinating side chains were present in proximal positions. © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
DA  - 2020
DO  - 10.1002/chem.202002454
LA  - eng
IS  - 69
M2  - 16357
PY  - 2020
SP  - 16357-16364
T2  - Chemistry - A European Journal
TI  - Suzuki-Miyaura Cross-Coupling of Bromotryptophan Derivatives at Ambient Temperature.
UR  - https://nbn-resolving.org/urn:nbn:de:0070-pub-29446570
Y2  - 2024-11-22T02:29:54
ER  -