Taxanes epoxide ring opening

Except for a few results concerning type A and B taxanes in which either esterification or saponification was used to confirm structures by comparison with known compounds, studies of opening of the epoxide rings (36), or determination of the structure of autoxidation products (55), most of the published chemistry has been effected on baccatin Ill-type compounds (13b). Thus, two synthetic approaches for structural modifications have been described in the literature using, in one case, taxol itself as starting material or, instead, 10-deacetylbaccatin III (13a), extracted from leaves (easily collected without causing damage to the tree). 

The Holton synthesis of the structurally-analogous taxane ring system involves acid-catalyzed rearrangement upon epoxide opening of P-... 

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