A Scalable Stereoselective Synthetic Route to the Valuable Chiral Epoxyketone Building Block (R)-N-(tert-butyloxycarbonyl)-5-methyl-1-[(S)-2-methyloxiran-2-yl]-1-oxohex-4-en-2-amine

Abstract A novel and efficient stereoselective synthesis of (R)-N-(tert-butyloxycarbonyl)-5-methyl-1-[(S)-2-methyloxiran-2-yl]-1-oxohex-4-en-2-amine has been developed. This compound serves as a valuable chiral building block, offering potential applications in the synthesis of biologically active molecules and pharmaceuticals. The synthetic route outlined herein starts from a carbonyl compound. A chiral hydroxyl-containing intermediate is obtained via a reduction reaction, followed by induced epoxidation, yielding the target compound with exceptional enantiomeric purity and high overall yield. Previously reported methodologies employing sodium hypochlorite and other reagents suffer primarily from poor chiral control, as well as unsatisfactory reaction reproducibility due to batch-to-batch variations of sodium hypochlorite. In contrast, our developed method circumvents these drawbacks, making it highly suitable for large-scale production. The structure and stereochemistry of the product were rigorously confirmed using nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry (MS), and high performance liquid chromatography (HPLC).