Ammonium Chloride → (3S)-tert-butyl 3-(hydroxymethyl)-2-azabicyclo[3.1.0]hexane-2-carboxylate

TBAF (7.27 mL of 1.0 M in THF, 7.27 mmol) was added dropwise over 5 min to a THF (30 mL) solution of (3S)-tert-butyl 3-((tert-butyldiphenylsilyloxy)methyl)-2-azabicyclo[3.1.0]hexane-2-carboxylate (mixture of cis/trans-isomers) (3.13 g, 6.93 mmol) and the mixture was stirred at ambient temperature for 4.75 h. After the addition of saturated NH4Cl solution (5 mL), most of the volatile material was removed in vacuo and the residue partitioned between CH2Cl2 (70 mL) and 50% saturated NH4Cl solution (30 mL). The aqueous phase was extracted with CH2Cl2 (30 mL) and the combined organic phase was dried (MgSO4), filtered, concentrated in vacuo and then exposed to high vacuum overnight. The crude material was purified using a flash chromatography (silica gel; 40-50% EtOAc/hexanes) to afford (3S)-tert-butyl 3-(hydroxymethyl)-2-azabicyclo[3.1.0]hexane-2-carboxylate (1.39 g, 94% yield) as a mixture of cis/trans-isomers and a colorless oil. [Note: the exact cis/trans-isomer ratio was not determined at this stage.] LC-MS (M+Na)+=236.20. 1H NMR (400 MHz, DMSO-d6, δ=2.5 ppm) δ ppm 4.70 (t, J=5.7, 1H), 3.62-3.56 (m, 1H), 3.49-3.44 (m, 1H), 3.33-3.27 (m, 1H), 3.08-3.04 (m, 1H), 2.07 (br m, 1H), 1.93-1.87 (m, 1H), 1.51-1.44 (m, 1H), 1.40 (s, 9H), 0.76-0.71 (m, 1H), 0.26 (m, 1H).

1. custommost of the volatile material was removed in vacuo
2. customthe residue partitioned between CH2Cl2 (70 mL) and 50% saturated NH4Cl solution (30 mL)
3. extractionThe aqueous phase was extracted with CH2Cl2 (30 mL)
4. dry with materialthe combined organic phase was dried (MgSO4)
5. filtrationfiltered
6. concentrationconcentrated in vacuo
7. customexposed to high vacuum overnight
8. customThe crude material was purified

ORD record

ord-b386108e23c546e2ac5a04b0a22378dd

Source dataset

uspto-grants-2016_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09303007B2