Question

In a robinson annulation, an α,-unsaturated carbonyl compound reacts with a carbonyl compound to afford a (new) cyclic α,-unsaturated ketone by a michael–aldol–dehydration sequence. draw the structure of the reactants that would combine to form the a ring of the steroid desoxy-19-nortestosterone (below) by a robinson annulation.

Answer 1

Robinson Annulation reaction is mainly done for the synthesis of six membered rings. This reaction is the combination of two reactions 1). Michael Addition Reaction and 2). Aldole Condensation.

The synthesis of desoxy-19-nortestosterone by Robinson Annulation is shown below,