Reductive Studies on 3-Oxidopyrylium-alkene [5 + 2] Cycloadducts: Access to Some Hydroxy Cycloheptenoids

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• The endo-isomers show a coupling constant (J) in the range of 5–7 Hz for the bridgehead protons whereas the corresponding protons in the exo-isomer show a coupling constant in the range of 0–2 Hz. For further discussions , see Sammes , P. G. ; Street , L. J. J. Chem. Res., synop. 1984 , 196 .
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