Glutarimide Alkaloids Through Multicomponent Reaction Chemistry

A concise four step synthetic route for glutarimide alkaloids of high biological interest is presented. The scaffold is accessed via an Ugi four component reaction, hereby introducing two points of variation. This is followed by a hydrolysis, a cyclization under mild conditions, and an amine deprotection. The diastereomers of the cyclized intermediate can be easily separated, thus leading to optically pure alkaloids. By this route, four natural products and ten derivatives were synthesized. The scope and limitations of the synthetic methodology were investigated.