Acetic Acid → 3,3a,4,5,6,6a-hexahydro-2H-pentalen-1-one

HRID 462771Notes

Reaction equation

COC(CCC/C=[C:9]1/[C:10](=[O:17])[CH:11]2[CH:15]([CH2:16]/1)[CH2:14][CH2:13][CH2:12]2)=O.[OH-].[Li+].C(O)(=O)C>CO>[CH:11]12[CH2:12][CH2:13][CH2:14][CH:15]1[CH2:16][CH2:9][C:10]2=[O:17]

Participants

Conditions

Temperature: 10 °C

Procedure

A stirred solution of 6-[(E)-(mixture of 3β and 3β)-hydroxyoct-1-enyl]-3-[(E)-4-methoxycarbonylbutylidene]bicyclo[3,3,0]octan-2-one (90 mg), prepared as described in Example 4 and predominantly in the 6β-configuration, otherwise known as (±)-methyl(5E,13E)-(9S),[mixture of (15R) and (15S)]-6a-oxo-6,9-methano-15-hydroxyprosta-5,13-dienoate, in methanol (2 ml) at 5° C. was treated with aqueous lithium hydroxide solution (1.5 ml; 1.0N). The resulting solution was stirred for 3.3 hours at 10° C. and was then treated with glacial acetic acid (0.1 ml). The methanol was removed in vacuo and the residue was diluted with ethyl acetate (10 ml), washed with hydrochloric acid (2N), then with water, and then with saturated aqueous sodium chloride solution, dried over anhydrous sodium sulphate and concentrated in vacuo, to give 3-[(E)-4-carboxybutylidene]-6-[(E)-(mixture of 3α and 3β)-hydroxyoct-1-enyl]bicyclo[3,3,0]octan-2-one (70.0 mg), thought to be in the 6β-configuration, otherwise known as (±)-(5E,13E)-(9S),[mixture of (15R) and (15S)]-6a-oxo-6,9-methano-15-hydroxyprosta-5,13-dienoic acid [NMR in deuterochloroform: multiplets at 6.6, 5.5, 4.8-3.7, 3.0-1.1, 1.1-0.7 p.p.m⟧

Workup

customThe methanol was removed in vacuo
additionthe residue was diluted with ethyl acetate (10 ml)
washwashed with hydrochloric acid (2N)
dry with materialwith water, and then with saturated aqueous sodium chloride solution, dried over anhydrous sodium sulphate
concentrationconcentrated in vacuo

Sources & evidence

ORD record: ord-8444afcb6dba4559979b26b713a2d9a1
Source dataset: uspto-grants-1985_05
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US04517202

Reaction notes

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