[C:1]([Si:5]([CH3:14])([CH3:13])[O:6][C@H:7]1[CH2:11][CH2:10][C@@H:9](O)[CH2:8]1)([CH3:4])([CH3:3])[CH3:2].C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.N(C(OCC)=O)=NC(OCC)=O.C1(P([N:60]=[N+:61]=[N-:62])(C2C=CC=CC=2)=O)C=CC=CC=1>O1CCCC1>[N:60]([C@H:9]1[CH2:10][CH2:11][C@H:7]([O:6][Si:5]([C:1]([CH3:4])([CH3:3])[CH3:2])([CH3:14])[CH3:13])[CH2:8]1)=[N+:61]=[N-:62]
To a 0° C. solution of (+)-(1R,3S)-3-(tert-butyl-dimethyl-silanyloxy)-cyclopentanol (745 mg, 3.44 mmol) (from Example 29b supra) and triphenyl phosphine (1.17 g, 4.47 mmol) (Aldrich) in anhydrous tetrahydrofuran (60 mL) was added dropwise diethyl azodicarboxylate (710 μL, 780 mg, 4.47 mmol) (Aldrich). After 2 to 3 minutes followed a dropwise addition of diphenylphosphoryl azide (950 μL, 1.23 g, 4.47 mmol) (Aldrich). The mixture was allowed to warm up slowly to room temperature stirred overnight and then partitioned between ethyl acetate and water. The organic layer was collected, dried over sodium sulfate, filtered, concentrated and the resulting residue was chromatographed on a silica gel column with a 0–20% diethyl ether in hexanes gradient to give (+)-(1S,3S)-(3-azido-cyclopentyloxy)-tert-butyl-dimethyl-silane as a colorless liquid. (Yield 589 mg, 70%).
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