Methyl propionate → (1RS,4SR,5RS)-4-(4-carbomethoxypentyl)-4-methyl-3,8-dioxabicyclo[3.2.1]octane-1-ethanol

HRID 2058137Notes

Reaction equation

HRID 2058137 reaction equation
[C:1]([O:5][CH3:6])(=[O:4])[CH2:2][CH3:3].C([N-]C(C)C)(C)C.[Li+].CS(O[CH2:20][CH2:21][CH2:22][C:23]1([CH3:34])[CH:29]2[O:30][C:26]([CH2:31][CH2:32][OH:33])([CH2:27][CH2:28]2)[CH2:25][O:24]1)(=O)=O.[Cl-].[NH4+]>O1CCCC1>[C:1]([CH:2]([CH3:3])[CH2:20][CH2:21][CH2:22][C:23]1([CH3:34])[CH:29]2[O:30][C:26]([CH2:31][CH2:32][OH:33])([CH2:27][CH2:28]2)[CH2:25][O:24]1)([O:5][CH3:6])=[O:4]

Participants

6

Reactant 4

HCID 11124Methyl propionateHCID 25517Ammonium ChlorideHCID 2724682Lithium diisopropylamideHCID 23349568(1RS,4SR,5RS)-4-(3-methanesulfonyloxypropyl)-4-methyl-3,8-dioxabicyclo[3.2.1]octane-1-ethanol

Product 1

HCID 23349561(1RS,4SR,5RS)-4-(4-carbomethoxypentyl)-4-methyl-3,8-dioxabicyclo[3.2.1]octane-1-ethanolYield 30%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Procedure

Methyl-2-lithio propionate is generated from methyl propionate (176 mg, 2 mM) and lithium diisopropylamide (2 mM) in tetrahydrofuran (5 ml) under nitrogen in the usual manner. To this reagent, (1RS,4SR,5RS)-4-(3-methanesulfonyloxypropyl)-4-methyl-3,8-dioxabicyclo[3.2.1]octane-1-ethanol (258 mg, 0.84 mM) in tetrahydrofuran (5 ml) is slowly added at -78° C. and stirred for two hours. The resulting mixture is allowed to warm to room temperature and stirred for an additional hour. This mixture is then poured into saturated aqueous ammonium chloride solution (5 ml) and extracted with ether (5×10 ml). The combined organic layers are dried (Na2SO4), the solvent is removed in vacuo and the residue is purified by column chromatography on silica gel (30 g) with ether-petroleum ether (4:1) to give (1RS,4SR,5RS)-4-(4-carbomethoxypentyl)-4-methyl-3,8-dioxabicyclo[3.2.1]octane-1-ethanol (71 mg, 30%) as a colorless oil.

Workup

  1. stirringstirred for an additional hour
  2. extractionextracted with ether (5×10 ml)
  3. dry with materialThe combined organic layers are dried (Na2SO4)
  4. customthe solvent is removed in vacuo
  5. customthe residue is purified by column chromatography on silica gel (30 g) with ether-petroleum ether (4:1)

Sources & evidence

ORD record
ord-3d4d993e07724cfbab757138d4f16c67
Source dataset
uspto-grants-1980_07
Patent number
US04215048

Reaction notes

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