Development of a new Lewis base-tolerant chiral LBA and its application to catalytic asymmetric protonation reaction

A new Lewis base-tolerant LBA (Lewis Acid Assisted Brønsted Acid) derived from La(OTf)(3) and (S)-HOP has been developed as a new chiral Brønsted acid. This acid has been successfully applied as a catalyst to asymmetric protonation reactions of silyl enol ethers of 2-substituted cyclic ketones.