Benzaldehyde → (3R,4S)-3-amino-1-benzyl-4-(3-boronopropyl)pyrrolidine-3-carboxylic acid

HRID 590703Notes

Reaction equation

HRID 590703 reaction equation
C([NH:4][C@:5]1([C:22](NC(C)(C)C)=[O:23])[C@@H:9]([CH2:10][CH2:11][CH2:12][B:13]2[O:17]C(C)(C)C(C)(C)[O:14]2)[CH2:8][NH:7][CH2:6]1)(=O)C.S([O-])([O-])(=O)=O.[Na+].[Na+].[CH:36](=O)[C:37]1[CH:42]=[CH:41][CH:40]=[CH:39][CH:38]=1.C(O[BH-](OC(=O)C)OC(=O)C)(=[O:46])C.[Na+].C(=O)([O-])[O-].[Na+].[Na+]>ClCCCl.C(O)(=O)C>[NH2:4][C@:5]1([C:22]([OH:23])=[O:46])[C@@H:9]([CH2:10][CH2:11][CH2:12][B:13]([OH:14])[OH:17])[CH2:8][N:7]([CH2:36][C:37]2[CH:42]=[CH:41][CH:40]=[CH:39][CH:38]=2)[CH2:6]1

Participants

8

Reactant 5

HCID 240BenzaldehydeHCID 10340Sodium CarbonateHCID 24436Sodium SulfateHCID 5049666Sodium triacetoxyborohydrideHCID 67516451(3R,4S)-3-acetamido-N-tert-butyl-4-(3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)propyl)pyrrolidine-3-carboxamide

Product 1

HCID 57331359(3R,4S)-3-amino-1-benzyl-4-(3-boronopropyl)pyrrolidine-3-carboxylic acidYield 54.4%

Reagents, catalysts & solvents 2

HCID 176Acetic AcidCatalystHCID 111,2-DichloroethaneSolvent

Procedure

A stirred solution of (3R,4S)-3-acetamido-N-tert-butyl-4-(3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)propyl)pyrrolidine-3-carboxamide (Example 8, step 4) (166 mg, 0.42 mmol) in anhydrous 1,2-dichloroethane (5 mL) was treated with anhydrous sodium sulfate (2 g) and benzaldehyde (69 mg, 0.65 mmol), stirred for 2.5 h, then treated with sodium triacetoxyborohydride (212 mg, 1.0 mmol) and glacial acetic acid (2 drops) and stirred for 18 h. Aqueous sodium carbonate (10%, 5 mL) was added and the mixture stirred for a few minutes and extracted with ethyl acetate (30 mL, then 2×10 mL). The combined organic solution was washed with water and saturated aqueous sodium chloride (20 mL each), dried (MgSO4), and concentrated. The crude material was deprotected and isolated using the method described for example 8, step 5 to afford (3R,4S)-3-amino-1-benzyl-4-(3-boronopropyl)pyrrolidine-3-carboxylic acid (70 mg, 44%) as a white semisolid. NMR (d6-DMSO) δ 7.62 (br s, 2 H), 7.44 (br s, 3 H), 4.30-4.60 (m, 2 H), 3.60-3.90 (m, 2 H), 3.35-3.50 (m, 2 H), 2.85 (m, 1 H), 2.50 (m, 1 H), 1.20-1.80 (m, 3 H), 0.60-0.80 (m, 2 H). MS (m+1): 307.3; MS (m−H2O+1): 289.2.

Workup

  1. stirringstirred for 18 h
  2. stirringthe mixture stirred for a few minutes
  3. extractionextracted with ethyl acetate (30 mL
  4. washThe combined organic solution was washed with water and saturated aqueous sodium chloride (20 mL each)
  5. dry with materialdried (MgSO4)
  6. concentrationconcentrated
  7. customisolated

Sources & evidence

ORD record
ord-239f9f959c95443aad80c42400c81b35
Source dataset
uspto-grants-2016_01
Patent number
US09233985B2

Reaction notes

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