A flexible, multistep parallel synthesis of spiperone analogues is described. A library of 4- substituted piperidines, assembled utilizing reductive amination and acylation protocols, was alkylated either homogeneously or heterogeneously, exploiting a product release only concept, to afford an oxa-series of spiperone analogues. Screening of the products at 5-HT2 and D2 receptors revealed 5-HT2A antagonists with improved selectivity compared to ...