Α,β-unsaturated diazoketones as versatile building blocks for the synthesis of hydroxylated piperidines, indolizidines and quinolizidines.

A four-step approach for the synthesis of dihydroxylated piperidine, quinolizidine and indolizidine systems is described employing α,β-unsaturated diazoketones as versatile building blocks. Unsaturated diazoketones were readily prepared from a Horner-Wadsworth-Emmons reaction between a diazophosphonate and amino-aldehydes. The strategy employs an asymmetric dihydroxylation reaction as the key step and is simple and straightforward enough to be extended to other nitrogen heterocycles.