| 内容提要: |
The first total synthesis of the alkaloid (-)-haliclonin Aisreported. The asymmetric synthesis relied on a novel organocatalytic asymmetric conjugate addition of nitromethane with 3-alkenyl cyclohex-2-enone to set the stereochemistry of the all-carbon quaternary stereogenic center. The synthesis also features a Pd-promoted cyclization to form the 3-azabicyclo[3,3,1]nonane core, a SmI2-mediated intermolecular reductive coupling of enone with aldehyde toform the requisite secondary chiral alcohol, ring-closing alkene and alkyne metathesis reactions to build the two aza-macro-cyclic ring systems, and an unprecedented direct transformation of enol into enone. |