Diethyl Ether → Abietatriene

HRID 496542Notes

Reaction equation

HRID 496542 reaction equation
S([O-])(=O)(=O)C.C([BH-]([CH2:11][CH3:12])CC)C.[Li+].[CH3:14][CH2:15][CH2:16][CH2:17][CH2:18][CH3:19].C(O[CH2:23][CH3:24])C>O1CCCC1>[CH3:14][CH:15]([C:16]1[CH:18]=[CH:17][C:19]2[C@:11]3([CH3:12])[C@@H:19]([CH2:11][CH2:12][C:18]=2[CH:17]=1)[C:23]([CH3:24])([CH3:24])[CH2:16][CH2:15][CH2:14]3)[CH3:23]

Participants

6

Reactant 4

HCID 3283Diethyl EtherHCID 8058HexaneHCID 85257MethanesulfonateHCID 23664628Lithiumtriethylborohydride

Product 1

HCID 6432211AbietatrieneYield 41.3%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

Under an inert atmosphere, the mesylate (21.5 mg, 0.06 mmol) was dissolved in tetrahydrofuran in a Schlenk flask equipped with a cold finger. Excess lithium triethylborohydride (263 μL, 1 M in tetrahydrofuran, 0.26 mmol) was added dropwise to the solution, the reaction was stirred at reflux for 6 hours and monitored by TLC (6:1 hexane:diethyl ether). The reaction was quenched with ice-cold H2O, extracted with hexane (3×), dried with MgSO4, filtered over a silica plug, and concentrated. (Walter, 1988) GC analysis indicated that an 85:15 mixture of levopimaradiene:abietatriene had been obtained in 41.3% yield (6.6 mg). The isomeric mixture was separated by argentic TLC (Li et al., 1995) (SiO2—AgNO3, 3 developments with 85:15 hexane:diethyl ether) giving pure abietatriene (Rf 0.96) (Kutney and Han, 1996) and pure levopimaradiene (Rf 0.92) as identified by de novo characterization based on 1H, COSY-DEC, 13C, DEPT-135, HSQC, and HMBC NMR, and GC/MS analyses.

Workup

  1. customequipped with a cold finger
  2. temperatureat reflux for 6 hours
  3. customThe reaction was quenched with ice-cold H2O
  4. extractionextracted with hexane (3×)
  5. dry with materialdried with MgSO4
  6. filtrationfiltered over a silica plug
  7. concentrationconcentrated
  8. addition(Walter, 1988) GC analysis indicated that an 85:15 mixture of levopimaradiene

Sources & evidence

ORD record
ord-deffd5f9a4154801b567adda6032c62f
Source dataset
uspto-grants-2005_09
Patent number
US06946283B2

Reaction notes

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