Synthetic studies on the ceveratrum alkaloid skeleton

Article abstract of DOI:10.1016/S0040-4020(96)00074-9

1-(2-Cyclohexenyl-1-carbonyl)-piperidine-2-carboxyaldehyde oxime (23) was prepared in 5 steps from pyridine-2-carboxaldehyde. Oxidation with NaOCl afforded the corresponding nitrile oxide which cyclized to give a 1:1 ratio of diastereomers 2aα,3,4,5,5aα,9,10,11aβ,11cα-decahydro-6H,8H-[1,2]benzisoxazolo[3, 4-ab]quinolizin-6-one (24A) and 2aα,3,4,5,5aα,9,10,11aα,11cα-decahydro-6H,8H-[1,2]benzisoxazolo[3, 4-ab]quinolizin-6-one (24B) in a best yield of 30%.