Methanesulfonic Acid → N-(benzenesulfonyl)-cis-4-(methanesulfonyloxy)-proline, methyl ester

HRID 460274Notes

Reaction equation

HRID 460274 reaction equation
[CH3:1][S:2]([OH:5])(=[O:4])=[O:3].C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.[CH3:25][O:26][C:27](=[O:43])[C@@H:28]1[CH2:32][C@@H:31](O)[CH2:30][N:29]1[S:34]([C:37]1[CH:42]=[CH:41][CH:40]=[CH:39][CH:38]=1)(=[O:36])=[O:35].C(N(CC)CC)C>CCOC(C)=O.C1(C)C=CC=CC=1>[C:37]1([S:34]([N:29]2[CH2:30][C@@H:31]([O:3][S:2]([CH3:1])(=[O:5])=[O:4])[CH2:32][C@H:28]2[C:27]([O:26][CH3:25])=[O:43])(=[O:36])=[O:35])[CH:38]=[CH:39][CH:40]=[CH:41][CH:42]=1

Participants

7

Reactant 4

HCID 6395Methanesulfonic AcidHCID 8471TriethylamineHCID 11776TriphenylphosphineHCID 18445902trans-1-Benzenesulfonyl-4-hydroxy-pyrrolidine-2-carboxylic acid methyl ester

Product 1

HCID 58825077N-(benzenesulfonyl)-cis-4-(methanesulfonyloxy)-proline, methyl esterYield 59%

Reagents, catalysts & solvents 2

HCID 1140TolueneSolventHCID 8857Ethyl AcetateSolvent

Procedure

In a two-neck 50 mL flask was combined 0.55 mL (8.42 mmol, 1.2 equiv.) of methanesulfonic acid and 20 mL of anhydrous toluene under N2 and a Dean-Stark trap. The solution was heated to reflux for 90 minutes, then cooled, and the trap removed. Triphenylphosphine (2.21 g, 8.42 mmol, 1.2 equiv.) was added with stirring, the solution was cooled to 0° C. (ice water bath), and 1.93 mL (9.83 mmol, 1.4 equiv.) of diisopropyl azidodicarboxylate was added slowly via syringe over 15 minutes. The bright yellow slurry was warmed to RT, compound 15 added (2.0 g, 7.02 mmol), then triethylamine (0.39 mL, 2.81 mmol, 0.4 equiv.), and the resulting yellow slurry was heated to ˜70° C. for two hours. The mixture was then cooled to room temperature, diluted with ˜25 mL EtOAc, and a white precipitate filtered off. The filtrate was concentrated, redissolved in EtOAc, loaded onto silica, and eluted with 2:1 EtOAc/hexanes to give 0.63 g (1.73 mmol, 59% yield based on 1.16 g of recovered starting material) of 16 as a colorless glass which crystallized on standing. 1H-NMR (400 MHz, CDCl3, δ ppm) 7.89 (dt, J=2 Hz, 7 Hz, 2H), 7.60 (tt, J=1 Hz, 8 Hz, 1H), 7.53 (td, J=2 Hz, 7 Hz, 2H), 5.14 (m, 1H), 4.57 (dd, J=3 Hz, 10 Hz, 1H), 3.71 (m, 1H), 3.69 (s, 3H), 3.62 (dq, J=1 Hz, 12 Hz, 1H), 2.94 (s, 3H), 2.52 (dq, J=1 Hz, 15 Hz, 1H), 2.32 (m, 1H); 13C-NMR (400 MHz, CDCl3, δ ppm) 171.47, 138.42, 133.67, 129.61, 127.94, 78.23, 59.33, 53.88, 53.07, 39.30, 37.41; m/z: 364 (M+1)+. See, for example, Anderson, N. G., et al.; J. Org. Chem.; 61(22), pp. 7955–7958 (1996), which is incorporated by reference in its entirety.

Workup

  1. customIn a two-neck 50 mL flask was combined
  2. temperatureThe solution was heated
  3. temperatureto reflux for 90 minutes
  4. temperaturecooled
  5. customthe trap removed
  6. additionwas added slowly via syringe over 15 minutes
  7. temperatureThe mixture was then cooled to room temperature
  8. filtrationa white precipitate filtered off
  9. concentrationThe filtrate was concentrated
  10. dissolutionredissolved in EtOAc
  11. washeluted with 2:1 EtOAc/hexanes

Sources & evidence

ORD record
ord-2527c935d22d42b7af6109b3f4481fe8
Source dataset
uspto-grants-2007_03
Patent number
US07196112B2

Reaction notes

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