Answer to Question #93830 in Organic Chemistry for White Tougen

Question

Acid-catalyzed cascade reactions are employed by nature and also by synthetic chemists in the construction of complex polycyclic molecules, including steroids. Provide a mechanism for the following multiple cyclization.

Answer 1

A cascade (or tandem) reaction is an intramolecular reaction that allows the organic synthesis of fairly complex multinuclear organic molecules from just one precursor (non-cyclic). In general, these reactions can include many stages, which, for the most part, are spontaneous and uncontrolled.

Depending on the initial product subjected to the acidic cascade synthetic process, a general reaction mechanism can be seen. For this, it is necessary to know the initial product subjected to the reactions, as well as the catalyst.

For example, the use of $BF_3$ as a catalyst can affect the “opening” of epoxy rings.

For a complete answer to the question, it is necessary to know the initial and final product of the synthesis!