Further Optimization of a Scalable Biocatalytic Route to (3R)‑N‑Boc-3-aminoazepane with Immobilized ω‑Transaminase

An efficient method for the synthesis of (3R)-N-Boc-3-aminoazepane with immobilized ω-transaminase (ω-TA) has been further optimized. In comparison with the crude enzyme powder or wet whole cells, this immobilized enzyme exhibits excellent activity and stability under the optimum process conditions, allowing 20 rounds of enzyme reuse without obvious loss of activity. This procedure simplified the workup and was performed on a multikilogram scale in a reproducible manner to yield (3R)-N-Boc-3-aminoazepane with 99.2% ee and 97.0% purity.