Tandem vinylogous 1,2-addition/anionic oxy-Cope reaction leading from butadiene sulfone to an orthogonally functionalized bicycle.

Here we present a transition metal-free synthesis of a rigid, orthogonally functionalized bicyclic sulfone, starting from readily available reagents. The transformation proceeds via a tandem vinylogous 1,2-addition/anionic oxy-Cope sequence, followed by a second vinylogous ketone addition. Stereochemical assignments suggest that the anionic oxy-Cope reaction proceeds exclusively through a boat-shaped transition state. The product of the two-step sequence can be further functionalized through subsequent chemo- and diastereoselective transformations, suggesting possible applications in medicinal chemistry or materials chemistry.