A fast and efficient protocol for the palladium(II)-catalyzed production of aryl ketones from sodium arylsulfinates and various organic nitriles under controlled microwave irradiation has been developed. The wide scope of the reaction has been demonstrated by combining 14 sodium arylsulfinates and 21 nitriles to give 55 examples of aryl ketones. One additional example illustrated that, through the choice of the nitrile reactant, benzofurans are also accessible. The reaction mechanism was investigated by electrospray ionization mass spectrometry and DFT calculations. The desulfitative synthesis of aryl ketones from nitriles was also compared to the corresponding transformation starting from benzoic acids. Comparison of the energy profiles indicates that the free energy requirement for decarboxylation of 2,6-dimethoxybenzoic acid and especially benzoic acid is higher than the corresponding desulfitative process for generating the key aryl palladium intermediate. The palladium(II) intermediates detected by ESI-MS and the DFT calculations provide a detailed understanding of the catalytic cycle.
In the wake of the coronavirus disease
2019 (COVID-19) pandemic,
staff and students at universities worldwide were forced to swiftly
adapt to distance learning in order to continue with tertiary education.
One of the main challenges we encountered during this period was a
marked disconnect between staff and students, leading to lower motivation
and engagement by both parties. To address this issue, we explored
the social media platform Instagram as an interactive communication
channel to engage first-year pharmacy students during an introductory
organic chemistry course. This led to the development of @kemipilot,
an open Instagram account where student questions were fielded and
answered by creating educational images and videos. Despite being
a small-scale study, the overwhelmingly positive student response,
as well as comparisons between Instagram and the university student
forum, suggest that Instagram may be a useful pedagogical tool to
complement existing distance learning platforms, even beyond the COVID-19
pandemic.
A protocol for Pd(II)-catalyzed desulfitative synthesis of aryl ketones from sodium aryl sulfinates and nitriles in continuous flow has been developed. The reactions proceed with microwave heating using microwave transparent tube reactors, affording the desired aryl ketones in fair to good yields. Microwave transparent aluminum oxide reactors were identified as a safe and thermostable alternative to borosilicate glass reactors.
We report a facile synthesis of 3-amidino indoles from indoles and cyanamides. The reaction is Pd(II)-catalyzed and proceeds via C-H bond activation of the indole in its 3-position followed by a 1,2-addition of the resulting indole-palladium σ-complex to a cyanamide, which provides the corresponding amidine. The preference for 4,5-diazafluoren-9-one (DAF) as the ligand is investigated using DFT calculations, and a plausible reaction pathway is presented.
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