Resiniferatoxin total synthesis

Resiniferatoxin (RTX) is a daphnane diterpenoid contained in the irritant latex of some succulent African Euphorbias. Its total synthesis has been described as a 40 step asymmetric synthesis (Wender et al., 1997 see below), but for clinical use RTX isolated from Euphorbia resinifera. 

In the course of a total synthesis of resiniferatoxin, an unexpected ring extension occurred, when 1,3-dioxane 236a was treated with an acid in chloroform. The ring extension was confirmed by acid-catalyzed rearrangement of diol 236b into dioxepane 237 (Scheme 70) <20040L4371>. 

Scheme 13. Final stages and completion of the total synthesis of resiniferatoxin (1).

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