Enantioselective Synthesis of a 3,5,5-Trialkylated Tetronic Acid Derivative

Asymmetric Construction of All-Carbon Quaternary Stereocenters by Chiral-Auxiliary-Mediated Claisen Rearrangement and Total Synthesis of (+)-Bakuchiol

“…The construction of asymmetric quaternary stereocenters remains a challenge in organic synthesis [ 1 , 2 , 3 ]. All-carbon quaternary stereocenters are found in a wide range of complex natural products which share such a structural motif, including (+)-hyperforin ( 1 ) [ 4 ], (+)-perforatumone ( 2 ) [ 5 , 6 ], (+)-vibsanin A ( 3 ) [ 7 ], and (+)-bakuchiol ( 4 ) [ 8 , 9 , 10 , 11 , 12 , 13 ] ( Figure 1 ). To achieve the total synthesis of these natural products, a practical method for constructing the quaternary stereocenter is necessary.…”