Alkynyl hydroxylamines: key precursors for 1,2-N/O heterocycles

1,2-N/O Heterocycles are privileged scaffolds found in numerous natural products and have been shown to exhibit diverse pharmacological properties. Additionally, these compounds have emerged as important synthons in organic chemistry. Recent years have witnessed immense interest in these heterocycles from both the medicinal and the synthetic chemistry community. In light of the ever-increasing demand for isoxazolidine, isoxazoline, isoxazole, 1,2-oxazinane, 1,2-oxazine and 1,2-oxazepine in drug discovery, this review highlights an overview of recent methods (up to 2024) for the synthesis of these heterocycles starting from alkynyl hydroxylamines. The mechanistic pathways and stereo-electronic factors affecting yield and selectivity of the products are briefly explained to generate the understanding needed for future developments in this domain.