C[Si](C)(C)[N:3]([C@H:8]([B:13]1[O:17][C@@H:16]2[CH2:18][C@@H:19]3[CH2:22][C@H:21]([C@:15]2([CH3:25])[O:14]1)[C:20]3([CH3:24])[CH3:23])[CH2:9][CH:10]([CH3:12])[CH3:11])[Si](C)(C)C.[ClH:28]>O1CCOCC1.C(OCC)C>[ClH:28].[CH3:25][C@:15]12[C@H:21]3[CH2:22][C@H:19]([C:20]3([CH3:23])[CH3:24])[CH2:18][C@H:16]1[O:17][B:13]([C@@H:8]([NH2:3])[CH2:9][CH:10]([CH3:12])[CH3:11])[O:14]2
To a solution of crude N,N-Bis(trimethylsilyl)-(1R)-1-[(3aS,4S,6S,7aR)-hexahydro-3a,5,5-trimethyl-4,6-methano-1,3,2-benzodioxaborol-2-yl]-3-methylbutylamine of Step 3 (79 g, 0.193 mol) in a mixture of dioxane (100 ml) and diethyl ether (200 ml), a 4 N solution of hydrogen chloride in dioxane (193 ml, 0.772 mol) was added, while cooling at 0° C. The mixture was then stirred at room temperature for 4 hours and concentrated. The residue was taken up with anhydrous hexane (500 ml) and a 2 M solution of hydrogen chloride in diethyl ether (48 ml, 0.096 mol) was added. The mixture was stirred at 0° C. for 1 hour, then concentrated. The residue was taken up with anhydrous hexane and the resulting suspension was stirred at room temperature overnight. The solid was collected by filtration and dried under vacuum affording 38.1 g of product (66% yield). A second crop (4.13 g, 7% yield) was obtained from the mother liquors.
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