Chlorotrimethylsilane → HCID 18657848, compound

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Reaction Steps

1.6M n-butyllithium (2.5 ml, 4 mmol) was dropwise added to a solution of diisopropylamine (0.64 ml, 4.6 mmol) in tetrahydrofuran (40 ml) under a nitrogen stream at -78° C. and the reaction solution was stirred for 45 minutes. A solution of (2S,4R)-N-tert-butoxycarbonyl-4-tert-butyldimethylsiloxy-2-(N-tert-butoxycarbonyl-2-pyrrolidon-4-yl)pyrrolidine (986 mg, 2 mmol, compound of Reference Example 5-1) in tetrahydrofuran (10 ml) was dropwise added to this solution, and the mixture was stirred at the same temperature for 2 hours. Then, p-toluenesulfonyl azide (945 mg, 4.8 mmol) was added thereto, and the mixture was stirred further for 1 hour. Then, trimethylsilyl chloride (1.29 ml, 10 mmol) was added to this reaction solution, and the mixture was stirred at room temperature for 1 hour. The reaction solution was concentrated under reduced pressure. A saturated sodium hydrogen carbonate aqueous solution was added to the residue, and then the mixture was extracted with methylene chloride (50 ml). The organic layer was washed with a saturated sodium chloride aqueous solution, then dried over anhydrous magnesium sulfate and concentrated under reduced pressure. The residue was subjected to silica gel column chromatography (Wakogel™ C-300, chloroform) to obtain (2S,4R)-2-(3-azido-N-tert-butoxycarbonyl-2-pyrrolidon-4-yl)-N-tert-butoxycarbonyl-4-(tert-butyldimethylsiloxy)pyrrolidine (720 mg, yield: 68.5%).

Provenance & Evidence