Tetrahydrofuran → tert-Butyl hydrogen (1,5-dihydroxypentan-2-yl)carbonimidate

HRID 1257571Notes

Reaction equation

C1COCC1.[Li+].[BH4-].[C:8]([O:12][C:13]([NH:15][C@@H:16]([CH2:21][CH2:22][C:23](OC)=[O:24])[C:17](OC)=[O:18])=[O:14])([CH3:11])([CH3:10])[CH3:9]>CO>[OH:18][CH2:17][C@@H:16]([NH:15][C:13](=[O:14])[O:12][C:8]([CH3:10])([CH3:9])[CH3:11])[CH2:21][CH2:22][CH2:23][OH:24]

Participants

Conditions

Temperature: 0 °C

Procedure

A 20 L reactor was charged with 10 L of dry THF and LiBH4 (400 g) and cooled to 0° C. A THF solution of (S)-dimethyl 2-(tert-butoxycarbonylamino)pentanedioate (1000 g/3.63 mol, dissolved in 2 L of dry THF) was then added dropwise while keeping the internal temp. below 15° C. The mixture was slowly warmed to room temperature and stirred for 16 h. Cooled to 0° C., then MeOH (10 L) was added dropwise to the reaction mixture to quench the excess amount of reducing reagent. Concentrated, and the residue was poured into 5 L water. After extraction with ethyl acetate, the combined organic phase was dried over Na2SO4. After filtration the solvent was removed in vacuo to give 730 g of crude (S)-tert-butyl 1,5-dihydroxypentan-2-ylcarbamate as a pale yellow oil.

Workup

custombelow 15° C
temperatureThe mixture was slowly warmed to room temperature
temperatureCooled to 0° C.
customto quench the excess amount of reducing reagent
concentrationConcentrated
additionthe residue was poured into 5 L water
extractionAfter extraction with ethyl acetate
dry with materialthe combined organic phase was dried over Na2SO4
filtrationAfter filtration the solvent
customwas removed in vacuo

Sources & evidence

ORD record: ord-e34b1d13c47d4946a7b4176add2ab383
Source dataset: uspto-grants-2013_06
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08461328B2

Reaction notes

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