Diketene → (R)-1-trichloromethyl-3-methyl-2-butenyl acetoacetate

HRID 127028Notes

Reaction equation

HRID 127028 reaction equation
[Cl:1][C:2]([Cl:10])([Cl:9])[C@H:3]([OH:8])[CH:4]=[C:5]([CH3:7])[CH3:6].C([O-])(=O)C.[Na+].[CH2:16]=[C:17]1[O:21][C:19](=[O:20])[CH2:18]1>C(Cl)Cl>[C:19]([O:8][C@@H:3]([C:2]([Cl:10])([Cl:9])[Cl:1])[CH:4]=[C:5]([CH3:7])[CH3:6])(=[O:20])[CH2:18][C:17]([CH3:16])=[O:21]

Participants

5

Reactant 3

HCID 12661DiketeneHCID 517045Sodium AcetateHCID 11095708(2R)-1,1,1-trichloro-4-methyl-3-penten-2-ol

Product 1

HCID 12525204(R)-1-trichloromethyl-3-methyl-2-butenyl acetoacetateYield 85.2%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

A mixture of (2R)-1,1,1-trichloro-4-methyl-3-penten-2-ol (1.50 g, 7.35 mmole) from Example IA.1.(a) and a trace of sodium acetate was treated under nitrogen at 100° with freshly distilled diketene (0.70 g, 8.36 mmole) added dropwise over 1 hr. After stirring and heating an additional hour at 80°-83°, the cooled reaction mixture was diluted with 3 ml of CH2Cl2 and chromatographed on 8 (20×20 cm) preparative tlc plates, developed in CH2Cl2. Isolation and extraction afforded (1R)-3-methyl-1-trichloromethyl-2-butenyl acetoacetate (1.80 g, 85% isolated yield) as a pale yellow oil; [α]D31 =+21.1° (hexane).

Workup

  1. additionadded dropwise over 1 hr
  2. temperatureheating an additional hour at 80°-83°
  3. customthe cooled reaction mixture
  4. customchromatographed on 8 (20×20 cm) preparative tlc plates
  5. extractionIsolation and extraction

Sources & evidence

ORD record
ord-b258cbfe111f45ddb48538a075daa307
Source dataset
uspto-grants-1981_03
Patent number
US04254282

Reaction notes

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