Bioactive piperidines are among the most common motifs in pharmaceuticals, yet accessing their chiral, highly substituted forms remains challenging. Now, a copper-catalysed reaction of amino-acid-derived cyclopropanols with aldehydes unites catalyst design with the natural chirality of reagents to access a broad family of stereodefined cis-2,6-disubstituted piperidines, expanding opportunities in drug discovery and natural product synthesis.