Development of an Efficient and Scalable Biocatalytic Route to (3R)-3-Aminoazepane: A Pharmaceutically Important Intermediate

An efficient and novel route to (3R)-3-aminoazepane (1) is described. The target is obtained with 99.92% purity, 99.2% ee in seven steps, and 46.2% overall yield. This improved method involves a practical biocatalytic transformation with ω-transaminase to establish the stereogenic center high efficiently as a key step. The developed process was scalable, cost-effective, with a simplified reaction workup, avoiding the use of expensive metal catalyst or chromatography, and commercially viable for the synthesis of 1.