Bispidine 1a is conveniently synthesized via a route involving double Manni
ch reaction of 1-allylpiperidin-4-one to N, N'-diallylbispidinone, Wolff-Ki
shner reduction of the bispidinone, and deallylation of the resulting N,N'-
diallylbispidine by treatment with ethyl chloroformate in the presence of N
aI, followed by alkaline hydrolysis.