(+-)-2-Butanol → beta-Cyclocitral

HRID 1608054Notes

Reaction equation

HRID 1608054 reaction equation
C([N-][CH:5]([CH3:7])[CH3:6])(C)C.[Li+].COCCO[AlH2-]O[CH2:16][CH2:17][O:18]C.[Na+].[CH3:21][CH:22](O)[CH2:23][CH3:24].[CH2:26]1COCC1>C1(C)C=CC=CC=1>[CH3:21][C:22]1[CH2:23][CH2:24][CH2:26][C:5]([CH3:6])([CH3:7])[C:16]=1[CH:17]=[O:18]

Participants

6

Reactant 4

HCID 6568(+-)-2-ButanolHCID 8028TetrahydrofuranHCID 2724682Lithium diisopropylamideHCID 16684438Red-Al

Product 1

HCID 9895beta-CyclocitralYield 67%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Procedure

2.0 G (0.011M) of methyl beta-cyclogeranate were slowly added at -78° to a solution of lithium diisopropylamide (1.05 equiv.) in 30 ml of THF. Once the introduction is over, the temperature of the reaction mixture was increased to 15° and 3.17 ml (0.011M) of a 70% solution of VITRIDE in toluene were rapidly added thereto. The reaction temperature was increased to 40° and after 45 mn, the mixture was treated with 4.07 g of 2-butanol (0.055M). After subjecting the mixture to the same treatments as those described in the previous example, 1.31 g of beta-cyclocitral was obtained by distillation at 45°-50°/1.33 Pa (yield: 67%). By carrying out the hydrolysis by means of a saturated aqueous solution of ammonium chloride or by means of aqueous HCl instead of 2-butanol, a mixture of beta-/gamma-cyclocitral was obtained with an isomeric content of about 70/30 respectively. In view of the fact that alpha-cyclocitral isomerizes easily to beta-cyclocitral, this latter compound can be easily synthesized starting from a mixture of methyl alpha- and beta-cyclogeranate or simply from the alpha-isomer.

Workup

  1. temperaturewas increased to 15°
  2. temperatureThe reaction temperature was increased to 40°

Sources & evidence

ORD record
ord-1927d5168bb14072a905efe6ab80dcce
Source dataset
uspto-grants-1989_09
Patent number
US04868340

Reaction notes

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