Divergent contiguous stereocenters via asymmetric conjugate additions to cycloalkenyl ketones

Simultaneously forming multiple stereogenic centers is an efficient synthetic strategy, but controlling contiguous centers in cyclic molecules is still challenging. Here, we describe asymmetric conjugate additions of alkyl nucleophiles to cyclic alkenes activated by an exocyclic ketone. This convergent approach assembles carbon–carbon bonds while producing two adjacent stereogenic centers, and the choice of workup selects for cis or trans 6-membered ring products. The method can also produce contiguous stereogenic centers in 5-, 7-, and 8-membered rings. A key to the success of this method was the development of non-C 2 -symmetrical phosphoramidite ligands featuring a stereogenic phosphorus.