[OH:1][N:2]=[C:3]([Cl:14])[C@H:4]1[CH2:8][O:7][C:6]2([CH2:13][CH2:12][CH2:11][CH2:10][CH2:9]2)[O:5]1.[CH3:15][S:16](Cl)(=[O:18])=[O:17].C(NC(C)CC(C)C)C>C1COCC1>[CH3:15][S:16]([O:1][N:2]=[C:3]([Cl:14])[C@H:4]1[CH2:8][O:7][C:6]2([CH2:13][CH2:12][CH2:11][CH2:10][CH2:9]2)[O:5]1)(=[O:18])=[O:17]In a 4 neck 5 L flask was added (R)-N-hydroxy-1,4-dioxaspiro[4.5]decane-2-carbimidoyl chloride (158 g, 719 mmol) in 2.5 L of THF. The material was cooled to 3° C. and methanesulfonyl chloride (56.1 ml, 719 mmol) added in 10 mL portions over 10 minutes. Next, N-ethyl-isopropylpropan-2-amine (126 ml, 719 mmol) was added through an addition funnel over 12 minutes. The reaction was stirred in the ice bath for 30 minutes and then at ambient temperature for 1 hour. The reaction was filtered and the solids washed with MTBE (about 3 L). The filtrate was concentrated and the residue was purified over silica gel (3 kg silica, 7:1 to 3:1 Hex/EtOAc) to afford an oil that slowly solidified under vacuum. The solids were ground using a mortar and pestle and washed with hexanes (about 1000 mL) and dried to afford (R)-N-(methylsulfonyloxy)-1,4-dioxaspiro[4.5]decane-2-carbimidoyl chloride (158 g, 531 mmol, 73.8% yield) as a white solid.
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