Biomimetic Total Synthesis of 6a,7,8,9,10,10a-Hexahydro-3,6,9-trimethyl-6-(4-methylpent-3-en-1-yl)-1,9-epoxy-6H-dibenzo-[b,d]pyran and Its Diastereoisomer

The first total synthesis of 6a,7,8,9,10,10a-hexahydro-3,6,9-trimethyl-6-(4-methylpent-3-en-1-yl)-1,9-epoxy-6H-dibenzo[b,d]pyran and its diastereoisomer via tandem pericyclic reactions were achieved in one step. Our biomimetic strategy features a sequential Aldol-type addition, 6 electrocyclization, and hetero-Diels-Alder cycloaddition, where three rings, two C-C bonds, and two C-O bonds were spontaneously constructed in a highly efficient way.