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The in‐depth study of electrochemical (EC) synthesis can require a powerful mass spectrometry (MS) analytical platform which can discover and identify fleeting intermediates in EC reactions. Here we report a floating electrolytic electrospray ionization (FE‐ESI) strategy that can perform EC processes in a floating electrolytic cell and monitor intermediates by high‐resolution MS. Compared with previous EC‐MS methods, a significant advantage of FE‐ESI‐MS is that it allows one to modulate the electrolytic and electrospray process individually, ensuring its high sensitivity in discovering intermediates and universality to investigate redox reactions in different scenarios. This powerful platform has been successfully used to investigate the EC reductive coupling of p‐tolylboronic acid and p‐nitrotoluene. A series of nitrene intermediates were discovered and identified by FE‐ESI‐MS, indicating that a hidden mechanism involving nitrene formation might play a key role in EC reductive coupling process. [ABSTRACT FROM AUTHOR]

Seven rare noreudesmane sesquiterpenoids (dysoxydenones M-S, 1–7), including three 11,12,13-trinoreudesmanes, three 13-noreudesmanes and one spirovetivane-type sesquiterpenoid, along with two known analogues were isolated from the fruits of Dysoxylum densiflorum. The planar structures were elucidated by a combination of 1D, 2D NMR and HRESIMS analyses. Their absolute configurations were determined by combination of single-crystal X-ray diffraction, CD exciton chirality method and ECD calculation. All compounds were screened for anti-inflammatory activity on LPS-induced RAW 264.7 cells and IL-1 β inhibitory activity. [Display omitted] • Seven rare noreudesmane sesquiterpenoids were isolated from fruits of Dysoxylum densiflorum. • Compounds 1‐3 were 11,12,13-trinoreudesmanes, 4–6 were rare 13-noreudesmanes, and 7 was spirovetivane-type sesquiterpenoid. • Their absolute configurations were determined by single-crystal X-ray diffraction and CD exciton chirality method. [ABSTRACT FROM AUTHOR]