Enantioselective Rhodium‐Catalyzed Addition of Arylboroxines to N‐Unprotected Ketimines: Efficient Synthesis of Cipargamin

Highly enantioselective rhodium‐catalyzed addition of arylboroxines to N‐unprotected ketimines is realized for the first time by employing chiral BIBOP‐type ligands with a Rh loading as low as 1 mol %. A range of chiral α‐trifluoromethyl‐α,α‐diaryl α‐tertiary amines or 3‐amino‐3‐aryloxindoles were formed with excellent ee values and yields by employing either WingPhos or PFBO‐BIBOP as the ligand. The method has enabled an efficient enantioselective synthesis of cipargamin.