The
applicability of a heteroaromatic photoredox catalyst in an
additive-free photo-mediated hydroamination of stilbenes is described.
Initiated by the excitation of a highly potent organic pyrimidopteridine
photoredox catalyst (E*[PrPPT*/PrPPT·
–] = +2.10 V vs SCE in MeCN), the photo-mediated
hydroamination of stilbenes was enabled using unprotected, primary
aliphatic, allylic, benzylic amines for the synthesis of various α-phenyl
phenethylamine derivatives. Notably, the stereogenic center of α-chiral
amines was fully preserved. Both starting materials serve as competent
quenching partners. Fluorescence- and competitive fluorescence-quenching
experiments as well as electron paramagnetic resonance spectroscopic
analysis and density functional theory calculations allowed a plausible
reaction mechanism to be deduced.
We report a sequential one-pot preparation of aromatic trifluoromethyl ketones starting from readily accessible aryl bromides and fluorosulfates, the latter easily prepared from the corresponding phenols. The methodology utilizes low pressure carbon monoxide generated ex situ from COgen to generate Weinreb amides as reactive intermediates that undergo monotrifluoromethylation affording the corresponding aromatic trifluoromethyl ketones (TFMKs) in good yields. The stoichiometric use of CO enables the possibility for accessing 13 C-isotopically labeled TFMK by switching to the use of 13 COgen.
Herein, we report a photomediated hydro- and deuterodecarboxylation
of different primary, secondary, and tertiary carboxylic acids catalyzed
by an organic pyrimidopteridine photoredox catalyst. The reaction
was optimized by a statistical design of experiment (DoE). Under optimized
reaction conditions, the conversion of commercially available nonsteroidal
anti-inflammatory drugs (NSAIDs) in tablet form and on gram scale
was realized. The scope of the application comprises primary, secondary,
and tertiary aliphatic biologically active carboxylic acids. A deuterium
incorporation of up to 95% by using D2O as inexpensive
deuterium source was achieved. A sensitivity assessment as well as
experiments aiding the elucidation of the reaction mechanism are discussed.
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