Total synthesis of (−)-5,6-seco-germacrane lactone

The first total synthesis of (−)-5,6-seco-germacrane lactone has been achieved. The synthetic highlight of our approach includes sp2-sp3 Suzuki-Miyaura cross coupling of a vinyl bromide and an alkyl 9-BBN derivative. The vinyl bromide was easily prepared from the chiral lactonic building block using a one-pot regioselective bromination. The asymmetric carbon center of the alkyl boron compound was formed using the zirconium-catalyzed carbomagnesation of 2,5-dihydrofuran.