Iodine → (2R,6R)-(+)-1-tert. Butoxy-2,6,10-trimethylundecane

HRID 26777Notes

Reaction equation

HRID 26777 reaction equation
[Mg].II.Br[CH2:5][CH2:6][C@H:7]([CH3:14])[CH2:8][CH2:9][CH2:10][CH:11]([CH3:13])[CH3:12].C1(C)C=CC(S(O[CH2:25][C@@H:26]([CH3:33])[CH2:27][O:28][C:29]([CH3:32])([CH3:31])[CH3:30])(=O)=O)=CC=1.OS(O)(=O)=O>O1CCCC1>[C:29]([O:28][CH2:27][C@H:26]([CH3:33])[CH2:25][CH2:5][CH2:6][C@H:7]([CH3:14])[CH2:8][CH2:9][CH2:10][CH:11]([CH3:13])[CH3:12])([CH3:32])([CH3:31])[CH3:30]

Participants

7

Reactant 5

HCID 807IodineHCID 1118Sulfuric AcidHCID 5462224MagnesiumHCID 12801557(R)-1-bromo-3,7-dimethyloctaneHCID 86735106(S)-(+)-3-tert. butoxy-2-methyl-1-propyl p-toluenesulfonate

Product 1

HCID 12923314(2R,6R)-(+)-1-tert. Butoxy-2,6,10-trimethylundecane

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent4×

Procedure

A mixture of 2.33 g. (0.097 mole) of powdered magnesium and a few iodine crystals in 23 ml. of dry tetrahydrofuran was stirred at reflux temperature while a solution of 17.9 g. (0.08 mole) of (R)-(-)-1-bromo-3,7-dimethyloctane in 51 ml. of dry tetrahydrofuran was added dropwise over 1 hour. The mixture was stirred at reflux for an additional 1 hour then cooled to room temperature. To a solution of 19.5 g. (0.065 mole) of (S)-(+)-3-tert. butoxy-2-methyl-1-propyl p-toluenesulfonate in 56 ml. of dry tetrahydrofuran, stirring at -78° C. was added the R-3,7-dimethyl-1-octyl magnesium bromide solution dropwise, followed by 3.3 ml. of a 0.1 M Li2CuCl4 solution in dry tetrahydrofuran. The resulting mixture was stirred at -78° C. for 10 minutes, for 2 hours at 0°-5° C. (ice bath) and finally for 18 hours at room temperature. At the end of this time, the reaction mixture was treated with 1 N aqueous H2SO4 and work up was carried out by extraction with ether in the manner of Example 1. The crude product was chromatographed on 450 g. of silica gel. Elution with 19:1 parts by volume hexane-ether gave the desired product which was distilled under high vacuum yielding 12.5 g. of (2R,6R)-(+)-1-tert. butoxy-2,6,10-trimethylundecane as a colorless oil, b.p. 91°-95° C. (0.3 mm Hg); [α]25D+0.94° (c 2.01, hexane).

Workup

  1. additionA mixture of 2.33 g
  2. temperatureat reflux temperature while a solution of 17.9 g
  3. temperatureat reflux for an additional 1 hour
  4. stirringThe resulting mixture was stirred at -78° C. for 10 minutes, for 2 hours at 0°-5° C. (ice bath)
  5. extractionup was carried out by extraction with ether in the manner of Example 1
  6. customThe crude product was chromatographed on 450 g
  7. washElution with 19:1 parts by volume hexane-ether

Sources & evidence

ORD record
ord-6e5df510d58a4a5e8e369cb4f9c3e39d
Source dataset
uspto-grants-1979_04
Patent number
US04151205

Reaction notes

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