(R)-2-Methyl-CBS-oxazaborolidine → HCID 54202943, compound

HRID 2301165Notes

Reaction equation

HRID 2301165 reaction equation
B1(C)[O:8][C:7]([C:15]2[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=2)([C:9]2[CH:14]=[CH:13][CH:12]=[CH:11][CH:10]=2)[C@@H]2N1CCC2>C1(C)C=CC=CC=1.C(Cl)Cl.C1COCC1>[CH:20]1([CH2:15][C@@H:7]([C:9]2[CH:10]=[CH:11][CH:12]=[CH:13][CH:14]=2)[OH:8])[CH2:19][CH2:18][CH2:17][CH2:16]1

Participants

5

Reactant 1

HCID 9838490(R)-2-Methyl-CBS-oxazaborolidine

Product 1

HCID 54202943HCID 54202943, compoundYield 81%

Reagents, catalysts & solvents 3

HCID 1140TolueneSolventHCID 6344DichloromethaneSolvent2×HCID 8028TetrahydrofuranSolvent

Procedure

A solution of 2.7 mL of 1.0 M (R)-2-methyl-CBS-oxazaborolidine solution in toluene in 4 mL of CH2Cl2 at −25° C. was treated with 1.4 mL of 2.0 M borane methyl sulfide complex in THF and stirred cold for 10 min. A solution of 501 mg (2.66 mmol) of cyclopentylmethylene phenyl ketone (from Step B) in 2 mL of CH2Cl2 was added over 25 min and the resulting mixture was stirred cold for an additional 45 min. The reaction was quenched by pouring it into cold (−25° C.) MeOH. The quenched reaction was warmed to rt and stirred for 45 min until gas evolution ceased. The mixture was concentrated and the residue dissolved in 20 mL of MeOH and concentrated again. Flash chromatography on silica gel using 17:3 v/v hexanes/EtOAc afforded 413 mg (81%) of the title compound: RF: 0.53 (4:1 v/v hexanes/ EtOAc); 1H NMR (300 MHz): δ 1.10-1.17 (m, 2H), 1.47-1.89 (m, 9H), 4.69 (m, 1H), 7.25-7.35 (m, 5H).

Workup

  1. stirringthe resulting mixture was stirred cold for an additional 45 min
  2. customThe reaction was quenched
  3. additionby pouring it into cold (−25° C.) MeOH
  4. customThe quenched reaction
  5. stirringstirred for 45 min until gas evolution
  6. concentrationThe mixture was concentrated
  7. dissolutionthe residue dissolved in 20 mL of MeOH
  8. concentrationconcentrated again

Sources & evidence

ORD record
ord-9d0c69bc85fc4626bc0158e032eb73f8
Source dataset
uspto-grants-2002_12
Patent number
US06498161B1

Reaction notes

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