Catalytic Asymmetric Synthesis of Aromatic Spiroketals by SpinPhox/Iridium(I)‐Catalyzed Hydrogenation and Spiroketalization of α,α′‐Bis(2‐hydroxyarylidene) Ketones

Abstract

From spiro to spiro: An iridium(I) complex with a spiral P,N ligand (SpinPhox) is highly efficient in the catalytic asymmetric hydrogenation of α,α′-bis(2-hydroxyarylidene) ketones to afford the corresponding aromatic spiroketals in high yields with excellent diastereo- and enantioselectivities (see scheme). The complex plays a dual role in the reaction, acting as catalyst for both the hydrogenation of CC bonds and the subsequent spiroketalization of bisphenolic ketones.