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Diels-Alder reactions between (E) -3-(3-methylbuta-I ,3-dienyl) -1 -tosylindole (3) and P-substituted acrylic acid derivatives are described. Reaction of (3) with maleic anhydride afforded the adduct (1 4). The latter compound in the presence of aluminium trichloride underwent intramolecular acylation with rearrangement to give 9methyl -6 -oxo-5tosyl-6,7,8,11 -tetra hydro -7,11 -met hano-5Hcyclo-oct[b] indole-I 2-carboxylic acid (1 6) and its double bond isomer (1 7) possessing a skeleton with a close resemblance to that of yuehchukene ( I ) , an antifertility agent. Compounds (16) and ( 17) were stereoselectively converted into the title compounds (28) and (29). The structures of two precursors, (24) and (25), of compounds (28) and ( 29) have been determined by X-ray crystallography.

ChemInform Abstract The alcohol (I), available from indole-3-carbaldehyde, is transformed to the tetracycle (IV) which represents the basic structure of the potent antifertility agent yuehchukene. Compound (IV) is coverted to 7,7-bis-nor-yuehchukene (VIII) via the intermediate benzoate (VI) (space group P1; Z=2).