Trimethylsilyldiazomethane → (e)-2-Methylcinnamic acid tert-butylamine salt

HRID 546334Notes

Reaction equation

HRID 546334 reaction equation
[Si](C=[N+:6]=[N-])(C)(C)C.[CH3:8][C:9]1[CH:20]=[CH:19][CH:18]=[CH:17][C:10]=1/[CH:11]=[CH:12]/[C:13]([O:15]C)=[O:14].C(OC)(=O)[C@H](C1C=CC=CC=1)O>C(Cl)(Cl)Cl>[C:9]([NH2:6])([CH3:20])([CH3:10])[CH3:8].[CH3:8][C:9]1[CH:20]=[CH:19][CH:18]=[CH:17][C:10]=1/[CH:11]=[CH:12]/[C:13]([OH:15])=[O:14]

Participants

5

Reactant 3

HCID 167693TrimethylsilyldiazomethaneHCID 643570methyl (2S)-2-hydroxy-2-phenylacetateHCID 101763492-Propenoic acid, 3-(2-methylphenyl)-, methyl ester, (2E)-

Product 1

HCID 67198081(e)-2-Methylcinnamic acid tert-butylamine salt

Reagents, catalysts & solvents 1

HCID 6212ChloroformSolvent2×

Procedure

(R)-2-Methyl-3-phenylpropionic acid tert-butylamine salt, reaction time 40 minutes, conversion 100%. The free acid was liberated by partitioning between dichloromethane and 2M HCl. The organic layer was dried (Na2SO4), filtered and the solvent was evaporated, then the product was distilled (kugelrohr, 150° C., 0.5 mbar) to give (R)-2-Methyl-3-phenylpropionic acid as a colorless liquid. [α]D25-22.7, c=1.02, CHCl3. Lit. (E. Tyrell, M. W. H. Tang, G. A. Skinner and J. Fawcett, Tetrahedron, 1996, 52, 9841-9852, [α]D20-23.1 c=1, CHCl3). ee 85% (derivatised using TMS-diazomethane, Chirasil Dex CB column, 25 m×0.25 mm, injector/detector 200° C., helium 20 psi, 100° C. for 21 minutes then ramp at 15° C./min to 200° C., hold for 5 minutes, retention times R 30.40 minutes, S 31.06 minutes, (E)-methyl 2-methylcinnamate, 34.79 minutes). 1H NMR analysis of the (S)-methyl mandelate (E. Tyrell, M. W. H. Tang, G. A. Skinner and J. Fawcett, Tetrahedron, 1996, 52, 9841-9852) confirmed assignment of (R)-configuration.

Workup

  1. customfor 21 minutes

Sources & evidence

ORD record
ord-7d3995f81d314a17aa24e72d721f4a63
Source dataset
uspto-grants-2011_05
Patent number
US07935841B2

Reaction notes

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