The preparation of collections of structurally diverse small molecules is a useful tool for studying biology and medicine with chemistry. Herein, we demonstrate the versatility of the pure enantiomers of 2-(2-oxo-ethyl)-piperidine-1-carboxylic acid tertbutyl ester to prepare the biological active alkaloids sedridine, allosedridine, methylsedridine, methylallosedridine, ethylnorlobelol, and coniine in two steps and in a stereoselective way via a reagent-based differentiation. The described syntheses are a demonstration of the versatility of 2-(2-oxo-ethyl)-piperidine-1-carboxylic acid tert-butyl esters as chiral building blocks. (c) 2005 Elsevier Ltd. All rights reserved.