Catalytic Asymmetric Claisen Rearrangement of Enolphosphonates: Construction of Vicinal Tertiary and All‐Carbon Quaternary Centers

A copper-catalyzed enantioselective Claisen rearrangement of easily accessible enolphosphonates using the commercially available PhBOX as the chiral ligand was developed. A wide range of rearrangement products with contiguous tertiary and all-carbon quaternary centers were obtained in excellent yields and stereoselectivities. The α-ketophosphonate substituent in the products could be easily transformed into other functional groups.