Hydrochloric Acid → 8-But-2-ynyl-10,10-difluoro-11-oxa-3,8-diazaspiro[5.5]undecane

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Reaction Steps

Tert-butyl 8-but-2-ynyl-10,10-difluoro-11-oxa-3,8-diazaspiro[5.5]undecane-3-carboxylate (50.0 mg, 0.145 mmol) was dissolved in dichloromethane (1 mL) and treated with HCl in dioxane (1.3 mL of 4 M, 5.1 mmol). The reaction mixture was stirred for 1 h then concentrated in vacuo several times with acetonitrile to yield a white solid. The solid was dissolved in 1:1 DCM/acetonitrile and stirred with solid K2CO3 for 1 h. The mixture was filtered and concentrated to provide 8-but-2-ynyl-10,10-difluoro-11-oxa-3,8-diazaspiro[5.5]undecane (34 mg, 96%). ESI-MS m/z calc. 244.1. found 245.3 (M+1)+; Retention time: 0.79 minutes (3 min run).

Provenance & Evidence