Photosensitized [4+2] cyclodimerizations of aromatic retinoids1

Metal–Organic Coordination versus Hydrogen Bonding: Highly Efficient Templated Photocycloadditions of Trisubstituted Isomeric Olefins in the Solid State

“…[27] Whereas the reactivity of trisubstituted olefins is well-documented in solution, such molecules remain largely unexplored as reactants in solids. [15] Solid-state photodimerizations of trisubstituted olefins have been generally limited to retinoids, [28][29] coumarins, [30] quinones, [31] and substituted cycloalkenes. [32] To our knowledge, a templated photodimerization of a trisubstituted olefin in the solid state has not been reported.…”

Direct On-Line Coupling of Capillary HPLC with 1H NMR Spectroscopy for the Structural Determination of Retinyl Acetate Dimers: 2D NMR Spectroscopy in the Nanoliter Scale

“…Kitols, natural retinol dimers, were initially found in whale liver oil. − Kitol and its derivatives were regarded as a 1,4 cycloaddition product of the 11,13-diene part of the first retinol molecule with the 13-monoene part of the second retinol molecule, leading to the formation of the central cyclohexene ring , (see Figure a). The spectroscopic data for kitols are based mainly on 1D 200 MHz 1 H NMR spectra 19 and only two structures, 2 and its 9‘-cis isomer 2a , have been discussed in the literature.…”