カイニン酸の全合成

抄録

Photolysis provides a powerful means for cleaving sp³C-H bonds adjacent to heteroatom such as nitrogen or oxygen but its application to complex organic synthesis is still relatively unexplored. Here, a new approach to kainic acid is reported, the key process of which is a novel photochemical sp³C-H bond carbamoylation of tertiary amine. The nitrogen-substituted sp³C-H bond of a cis-fused azabicyclo[4.3.0]nonane derivative was directly carbamoylated with phenyl isocyanate under UV irradiation to yield the proline motif of kainic acid. With the highly functionalized motif in possession, further chemical transformations that include silicon-directed regioselective Baeyer-Villiger oxidation were operated to successfully access the neuroexcitatory alkaloid.