Phosphazene-catalyzed desymmetrization of cyclohexadienones by dithiane addition

Abstract

We report a desymmetrization of cyclohexadienones by intramolecular conjugate addition of a tethered dithiane nucleophile. Mild reaction conditions allow the formation of diversely functionalized fused bicyclic lactones. The products participate in facially selective additions from the convex surface, leading to allylic alcohol derivatives.

Enantioselective α-Functionalization of 1,3-Dithianes by Iridium-Catalyzed Allylic Substitution

“…After an extensive screening process, the reaction conditions were optimized as follows: the coupling reaction was performed with 3.0 equiv of K 3 PO 4 , 0.2 equiv of t -BuOK, 2 mol % [Ir­(cod)­Cl] 2 , 4 mol % ( S , S , S )- L1 , and 10 mol % TBD in THF at 50 °C for 6 h. In addition, no linear product was observed in this reaction system. The coordination of 1,3-dithiane motif with the iridium catalyst might help explain the observed excellent regioselectivity …”