89. Asymmetric Total Synthesis of (−)-Cebulactam A1

Shouliang Yang, Yumeng Xi, Jia-Hua Chen* and Zhen Yang*

Org. Chem. Front., 2014, 1, 91-99

The total synthesis of (−)-cebulactam A1 (3) has been achieved for the first time in 18 steps. The key steps in this synthesis included an asymmetric chelation-controlled vinylogous Mukaiyama aldol reaction for the stereoselective synthesis of the stereogenic centers at the C8 and C9 positions, an intramolecular SmI₂-mediated Reformatsky reaction for the formation of a macrocyclic lactam, and an S_N2′ reaction for the stereoselective formation of the (E)-double bond linked tetrahydropyran moiety of cebulactam A1 (3).