Asymmetric construction of all-carbon quaternary stereocenters by chiral-auxiliary-mediated Claisen rearrangement and total synthesis of (+)-bakuchiol.

An asymmetric Claisen rearrangement using Oppolzer’s camphorsultam was developed. Under thermal conditions, a geraniol-derived substrate underwent the rearrangement with good stereoselectivity. The absolute configuration of the newly formed all-carbon quaternary stereocenter was confirmed by the total synthesis of (+)-bakuchiol from the rearrangement product.