An efficient 1,2,4-triazine-based route to the louisianin alkaloids

A new, short and efficient route to louisianins C and D is described in which the pyridine ring is constructed from a disubstituted 1,2,4-triazine by an inverse-electron-demand Diels-Alder/retro-Diels-Alder/aromatisation cascade sequence. This eight-step route produces louisianin C in 16% overall yield from the commercially available 5-chloropent-1-yne.