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

Participants

Reaction Conditions

Reaction Steps

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⟧

Provenance & Evidence