How is 3-Benzyl-3,9-diazaspiro[5.5]undecane (CAS: 189333-49-1) typically synthesized?

3-Benzyl-3,9-diazaspiro[5.5]undecane (CAS: 189333-49-1) can be synthesized via a multistep process involving the condensation of an appropriate diazabicycloalkane with a benzyl halide. The reaction typically proceeds under mild conditions using a Lewis acid catalyst, such as aluminum chloride, to promote the formation of the spiro compound. The yield is generally good, and the method is selective for the desired product.