Beilstein J. Org. Chem.2023,19, 448–473, doi:10.3762/bjoc.19.35
and Wang used a similar approach for the 2,2,2-trifluoroethoxylation of benzaldehydes under palladium catalysis using the amino acid 51 as organic catalyst in the presence of the fluoropyridiniumsalt 52 (19 examples, up to 88% yield, Scheme 23) [183]. Pleasingly, the methodology was extended to the
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Graphical Abstract
Scheme 1:
Transition-metal-catalyzed C–XRF bond formation by C–H bond activation: an overview.
Beilstein J. Org. Chem.2021,17, 1752–1813, doi:10.3762/bjoc.17.123
salt; fluoropyridiniumsalt; fluorosulfonimide; Introduction
Fluorinated organic compounds occupy an important position in pharmaceuticals [1], agrochemicals [2], and materials [3]. Especially, in the first two areas, the presence of fluorine has attracted attention during the last decades. Nowadays
(C5H5NH)BF4(BF3OH), which was a 1:1 mixture of the N-fluoropyridiniumsalt and N-hydropyridinium salt (anion parts; BF4 and BF3OH), based on an X-ray diffraction study of a commercial sample [42].
1-6. N-Fluoroquinuclidinium fluoride
In 1986 as the N-F pyridinium reagents were emerging, Banks et al
gave higher yields than the non-chloro reagent 9-1 because of the greater reactivity of 17-2.
1-18. Zwitterionic N-fluoropyridinium salts
In 1995, Umemoto and co-worker disclosed a zwitterionic N-fluoropyridiniumsalt system 18-2 which had a broad fluorinating power and high selectivity [76]. A series