A versatile synthesis of diazirine-based photoreactive fatty acid analogues is reported. The key step is phenoxy alkylation of diazirine with halo alkyl acid esters. The conditions described will be acceptable for the synthesis of various alkyl-length derivatives. The fatty acid derivatives are acceptors for reverse reactions of sphingolipid ceramide N-deacylase (SCDase), which catalyzes the condensation of psychosine and fatty acids to form ...