Secologanin chemical transformation

The simple chemical transformations of secologanin are summerized in Fig. (4). It is well known from the early literature that secologanin (1) can easily be hydrogenated at position 8,10 to (2) without saturation of the conjugated C=C bond [1]. The presence or absence of the 8(10) double bond (vinyl and ethyl, natural and dihydro derivatives, respectively) often... 

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