A Total Synthesis of (−)-Hamigeran B and (−)-4-Bromohamigeran B

A concise synthesis of (−)-hamigeran B and (−)-4-bromohamigeran B is presented. The key reactions include a Suzuki coupling of enol triflate 15 with arylboronic ester for efficient synthesis of the densely 1,2,3-trisubstituted cyclopentene 23, a coordination-controlled intramolecular Friedel–Crafts cyclization of free phenol 13 for highly regioselective construction of tricyclic core 12, and a LiOH/O2-promoted hydrolysis and concomitant aerobic oxidation of 31 for atom- and step-economic accessing of diketone 32. The application of these key transformations allowed for a rapid and efficient synthesis of (−)-hamigeran B and (−)-4-bromohamigeran B in 13 steps from the readily available chiral material 18.