Dichloromethane → Benzyl trans-3-[(tert-butoxycarbonyl)amino]-2-methylpiperidine-1-carboxylate

HRID 1050558Notes

Reaction equation

HRID 1050558 reaction equation
[CH3:1][C@@H:2]1[CH:7]([NH:8][C:9](=[O:15])[O:10][C:11]([CH3:14])([CH3:13])[CH3:12])[CH2:6][CH2:5][CH2:4][NH:3]1.C(Cl)Cl.CCN(C(C)C)C(C)C.Cl[C:29]([O:31][CH2:32][C:33]1[CH:38]=[CH:37][CH:36]=[CH:35][CH:34]=1)=[O:30]>O>[C:11]([O:10][C:9]([NH:8][C@@H:7]1[CH2:6][CH2:5][CH2:4][N:3]([C:29]([O:31][CH2:32][C:33]2[CH:38]=[CH:37][CH:36]=[CH:35][CH:34]=2)=[O:30])[C@@H:2]1[CH3:1])=[O:15])([CH3:14])([CH3:13])[CH3:12].[C:11]([O:10][C:9]([NH:8][C@@H:7]1[CH2:6][CH2:5][CH2:4][N:3]([C:29]([O:31][CH2:32][C:33]2[CH:38]=[CH:37][CH:36]=[CH:35][CH:34]=2)=[O:30])[C@H:2]1[CH3:1])=[O:15])([CH3:14])([CH3:13])[CH3:12]

Participants

7

Reactant 4

HCID 6344DichloromethaneHCID 10387Benzyl chloroformateHCID 81531DiisopropylethylamineHCID 118114667(R)-tert-butyl 2-methylpiperidin-3-ylcarbamate

Product 2

HCID 59223903(2R,3R)-benzyl 3-(tert-butoxycarbonylamino)-2-methylpiperidine-1-carboxylateYield 19%HCID 59224206Benzyl trans-3-[(tert-butoxycarbonyl)amino]-2-methylpiperidine-1-carboxylateYield 61%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Conditions

Temperature
0 °C

Procedure

(R)-tert-Butyl 2-methylpiperidin-3-ylcarbamate (307) (8.2 g, 38 mmol) was suspended in a solution of DCM (500 mL) and DIEA (13.4 mL, 76.9 mmol). Benzyl chloroformate (6.6 mL, 46 mmol) was then added drop-wise over 5 minutes and the reaction was stirred at 0° C. for 30 minutes. Water was then added and the mixture was allowed to come to room temperature and stirred for 30 minutes. The organic phase was separated, washed with 1M HCl (aq), saturated NaHCO3 (aq), and brine. On TLC, the trans-isomer (309) displayed a higher silica Rf value than the cis isomer (308). The two diastereomers were separated by silica flash column chromatography (EtOAc/hexanes). The mixed fractions from the first purification were combined and subjected to a second purification. After two purifications, (2R,3R)-benzyl 3-(tert-butoxycarbonylamino)-2-methylpiperidine-1-carboxylate (308) (2.5 g, 7.2 mmol, 19% yield) and (2S,3R)-benzyl 3-(tert-butoxycarbonylamino)-2-methylpiperidine-1-carboxylate (309) (8 g, 23 mmol, 61% yield) were obtained.

Workup

  1. customto come to room temperature
  2. stirringstirred for 30 minutes
  3. customThe organic phase was separated
  4. washwashed with 1M HCl (aq), saturated NaHCO3 (aq), and brine
  5. customThe two diastereomers were separated by silica flash column chromatography (EtOAc/hexanes)
  6. customThe mixed fractions from the first purification
  7. customsubjected to a second purification

Sources & evidence

ORD record
ord-c3f56fb6c9604cdd94323fc08010d1d5
Source dataset
uspto-grants-2016_07
Patent number
US09382246B2

Reaction notes

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