Allylic vicinal diols, rearrangements with

With the preparation of racemic drhydroisocodeine (79), Chida reported a formal synthesis of morphine [52], The synthesis is based on a cascade of sequential Claisen rearrangements of an allylic vicinal diol derivative as key steps. The Claisen rearrangement protocol, as an efficient strategy for the installation of the C13 quaternary carbon, was successfully employed in the preparation of the Amaryllidaceae alkaloid galanthamine, published 1 year before the synthesis of dihydroisocodeinone [64],... 

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