Numerous natural and non-natural products with interesting biological activities contain in their structure a piperidine core of type A, possessing a quaternary stereogenic center at C3 with the (R)- or (S)-configuration. These piperidines of type A are present in non-natural products such as capromorelin,(1) or in natural products such as isonitramine(2) and sibirine(2a, 3) (Figure 1). Piperidines of type B can be the precursors of piperidines of type A and can be ...