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The digital revolution sets a milestone in the progressive miniaturization of working devices and in the underlying advent of molecular machines. Foldamers involving mechanically entangled components with modular secondary structures are among the most promising designs for molecular switch‐based applications. Characterizing the nature and dynamics of their intramolecular network following the application of a stimulus is the key to their performance. Here, we use non‐dissociative electron transfer as a reductive stimulus in the gas phase and probe the consecutive co‐conformational transitions of a donor‐acceptor oligorotaxane foldamer using electrospray mass spectrometry interfaced with ion mobility and infrared ion spectroscopy. A comparison of collision cross section distributions for analogous closed‐shell and radical molecular ions sheds light on their respective formation energetics, while variations in their respective infrared absorption bands evidence changes in intramolecular organization as the foldamer becomes more compact. These differences are compatible with the advent of radical‐pairing interactions. [ABSTRACT FROM AUTHOR]

Uronic acids are important constituents of polysaccharides found on the cell membranes of different organisms. To prepare uronic‐acid‐containing oligosaccharides, uronic acid 6,3‐lactones can be employed as they display a fixed conformation and a unique reactivity and stereoselectivity. Herein, we report a highly β‐selective and efficient mannosyl donor based on C‐4 acetyl mannuronic acid 6,3‐lactone donors. The mechanism of glycosylation is established using a combination of techniques, including infrared ion spectroscopy combined with quantum‐chemical calculations and variable‐temperature nuclear magnetic resonance (VT NMR) spectroscopy. The role of these intermediates in glycosylation is assayed by varying the activation protocol and acceptor nucleophilicity. The observed trends are analogous to the well‐studied 4,6‐benzylidene glycosides and may be used to guide the development of next‐generation stereoselective glycosyl donors. [ABSTRACT FROM AUTHOR]