Catalytic asymmetric synthesis of guaiazulene analogues

Abstract

The asymmetric Michael addition reaction of guaiazulene to α,β-unsaturated 2-acyl imidazoles was developed with a chiral-at-metal Rh(III) complex as the catalyst for the first time. The corresponding adducts were obtained in good yields (76–98%) with excellent enantioselectivities (up to 99%). The reaction could be conducted on a gram-scale with a low catalyst loading (0.05 mol%) without impacting its efficiency. DFT studies rationalize the enantioselectivity of the reaction.