Trimethylsilyl iodide → (4S,10aS)-4-aminohexahydro-2H-pyrido[2,1-b][1,3]thiazepin-5(7H)-one

To a solution of benzyl (4S,10aS)-5-oxooctahydro-2H-pyrido[2,1-b][1,3]thiazepin-4-ylcarbamate (103 mg, 0.308 mmol) in DCM (2 mL) stirred at rt was added iodotrimethylsilane (0.054 mL, 0.40 mmol) dropwise. After addition, the resulting yellowish solution was stirred at rt under argon for 1 hr. Additional TMSI (0.054 mL, 0.40 mmol) was added. The yellowish reaction mixture stirred for an additional 1 hr. The reaction was quenched by addition of a drop of 1 N aqueous HCl and then diluted with EtOAc. The organic layer extracted with aqueous 1 N HCl (2×2.5 mL). The combined HCl extracts were washed with EtOAc and basified with 1 N aqueous NaOH solution to pH 9-10. The aqueous solution was extracted with DCM (3×10 mL). The combined DCM extracts were washed with saturated aqueous NaCl, dried over Na2SO4, filtered and concentrated to give (4S,10aS)-4-aminohexahydro-2H-pyrido[2,1-b][1,3]thiazepin-5(7H)-one (50.8 mg, 0.254 mmol, 82% yield) as a colorless oil. Anal. Calcd. for C9H16N2OS m/z 200.3. found: 201.3 (M+H)+; 1H NMR (400 MHz, CDCl3) δ ppm 5.33 (t, J=3.8 Hz, 1H), 4.37-4.24 (m, 1H), 4.07 (dd, J=10.0, 4.5 Hz, 1H), 3.06-2.87 (m, 2H), 2.63 (ddd, J=14.5, 7.5, 3.2 Hz, 1H), 2.27-2.15 (m, 1H), 2.03-1.92 (m, 2H), 1.92-1.77 (m, 3H), 1.76-1.41 (m, 4H).