Hydrindan skeleton

X-Ray analyses of two heavy-atom derivatives of illudol (203) and marasmic acid (204) have confirmed the ds-fused hydrindane skeletons in each and this fact is in accord with the stereochemistry of the hypothetical precursor (205) derivable from humulene. Matsumoto and co-workers have now completed... 

Treatment of the alkenyl iodide 147 with t-butyllithium in pentane/ether at —78 °C led to the anion 148 which rearranged in a regiospecific manner to give the cis-hydrindane skeleton 149 via generation of a quartemary center. 

Cyclizing the alkylated thiophene with sulfuric acid generates the c/.t-hydrindane skeleton 5 exclusively41. 

Palladium-catalyzed cyclization of 1,6-enynes is also applicable to cyclopentannulation if carbocycles are introduced with the substrate. This is demonstrated by a stereoselective palladium-catalyzed tandem alkylation/Alder ene cyclization starting from methyl ew-5-acetoxy-3-cyclohexene-l-carboxylate and dimethyl 2-(2-propynyl)malonate to give a single product with a cu-fused hydrindane skeleton in up to 85 % yield30. Similar conversions of preformed enynes or dienes have been reported95,90. 

Chiloschyphone (1) is a sesquiterpene ketone isolated from Chiloscyphus polyanthos and its absolute configuration has not been determined (3). The structure of this compound was first reported in 1972 (4), but later a total synthesis of this compound revealed that this original structure was wrong (5). Quite recently the correct structure was proposed by Connolly and his co-workers to be that depicted as in 1 (3). The synthesis of this correct structure has not been achieved yet. We plan to introduce cw-dimethyl groups by 1,4-addition, followed by an intramolecular aldol cyclization to yield a hydrindane skeleton (Scheme 1). The optical resolution must be possible at the stage of compound 4. 

Let us first consider the problem of obtaining a trans-C/D linkage in bi-cyclic intermediates of total synthesis with the hydrindan skeleton. The... 

Pattenden also proposed a novel type of cascade for the steroid skeleton construction [39]. Starting from the relatively elaborated precursor 78, that notably bears a cyclopropyl ring, a double 6-endo-trig creates cw-hydrindane 80 (Scheme... 

The enormous potential of the intramolecular Heck reactions has been demonstrated impressively in elegant syntheses of even the most complicated natural product skeletons. The intramolecular Heck reaction on the achiral iodoalkenes 354 and the corresponding alkenyl triflates 357 with their pairs of enantiotopic double bonds in the cyclohexa-1,4-diene moieties, applying catalysts with chiral ligands, gave tetrahydronaphthalenes 359 or hydrindanes from precursors such as 354, 357 or corresponding precursors with one less carbon in the tether [204f], with excellent enantioselectivities. Complementary to the asymmetrically induced inter-molecular arylation with triflates (Scheme 8.72), reasonable asymmetric inductions in intramolecular reactions were also achieved with iodides on the addition of silver salts to promote the formation of cationic intermediates such as 356 (Scheme 8.73)... 

Several new acids related to spiculoic add A were found subsequently in the species Plakortis zyggompha harvested in Martinique. These contain all the original skeleton of trans-hydrindan-2-one and a detailed structural study has revealed the definitive stereochemistry of all compounds of this family (Berrue et al, 2005a, 2007). AH of these polyketide-type derivatives are moderately cytotoxic or antimycobacterial. 

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