PubMed · 826193
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F Vögtle, K Frensch. 1976. Papaverine crown ethers.. https://doi.org/10.1002/anie.197606851
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In aqueous solution, a deep-cavity cavitand was shown to self-assemble into dimeric nano-capsules via the sequestration of gaseous-phase hydrocarbons. The sequestration, assembly, and entrapment process was shown to be dependent on the hydrocarbon. Thus, by way of example, butane could be selectively sequestered from a propane-butane mixture.
An asymmetric synthesis of enantioenriched, highly functionalized fluorinated carbocycles has been developed based on an enantioselective Sharpless dihydroxylation of cyclohexadienylsilanes, combined with a diastereoselective electrophilic fluorodesilylation. Several parameters define the level of diastereocontrol for the fluorination step. These include the relative stereochemistry of the starting endocyclic allylsilanes and the structural features of the reactants. As expected for an S(E)2' mechanism, the fluorodesilylation occurred with clean transposition of the double bond, with the attack of the electrophilic fluorinating agent taking place preferentially anti to the silyl group. For the fluorination step, the best selectivities were observed for the monocyclic anti,syn benzyl-protected precursors and for the syn,syn starting allylsilane. Full NMR spectroscopic analysis of the fluorinated monocyclic compounds, which possess an endocyclic double bond flanked by two electronegative groups (the methoxy group and the fluorine substituent) revealed that a subtle combination of steric (1,3-axial/pseudoaxial interaction) and stereoelectronic effects (pi-sigma* interaction) favours the preferential conformers featuring the methoxy group in a pseudoaxial position.
Vibrational sum frequency generation setup for the study of Langmuir film of cavitands molecules deposited at the water surface.