A Decalones

ETHYL BENZOATE VIA THE NITRO-SOAMIDE DECOMPOSITION, 47, 44 Decachlorobi-2,4-cyclopentadienyl, dechlorination by triisopropyl phosphite, 46, 93 a-Decalones, 46, 82 Decanoyl fluoride, 46, 6 Decarboxylation, in formation of couma-rone from o-formylphenoxyacetic acid, 46, 28... 

If the enone is part of a decalone system, i.e., a / - and an y-substituent are present, on reaction with lithiated areneacetonitriles in THF the exclusive formation of (Tv-substituted decalones is observedl26. The diastereoselectivity at the exocyclic stereogenic center is, however, poor. Applications in the synthesis of anthracyclines are given in the literature127,12S. 

The isomerization observed in the methylenation of c/s-a-decalones has been turned to good advantage. Mixtures of cis- and tra/is-isomers of the a-decalones (44) and (46) gave only the /ra/i -decalins (45) and (47). 

Intramolecular cyclizationlenolate trapping of allylsilanes (cf., 12,496-497).3 The intermediate enolate formed in the TiCl4-catalyzed cyclization of 1 can be trapped by chloromethyl methyl sulfide to give a decalone derivative with a potential methyl group on the angular position. Actually the reaction results in... 

The directing effect of an allylic silicon atom is also manifested in hydroboration [106]. This exquisite control is extendable to tetrasubstituted olefins [107] making the access of trans-a-decalones quite readily. 

By equatorial attack on the carbonyl, a single stereoisomer is formed from tert-butylcyclohexanone. In the presence of sodium alcoholate, 84 is formed from a butadienyl-sulfonium salt with an aldehydeThe reaction is stereospecific with 85 for instance, with aldehydes the trans product is obtained.An interesting stereospecific intramolecular methylene transfer has been observed for a decalone derivative. Stereoselective epoxidation has recently been described with 79 predominantly, the trans product results. Epoxidation can be carried out in a one-pot procedure at room temperature, with MejS + Me2S04, then NaOMe formed in situ. ... 

Among the non-steroidal alcohols applied to the Oppenauer oxidation are the cis and trans a-decalols (14), which give excellent yields of the corresponding a-decalones (IS).22 Oxidation of phenolic compounds bearing pendent aliphatic secondary alcohols can be readily performed without prior protection of the phenolic alcohol functionality.23 Acid-sensitive acetal 16 is smoothly converted to the corresponding ketone 17, by exploiting a modified experimental procedure.3,24... 

To a solution of cw-a-decalol (14,1.5 g, 9.9 mmol) in dry benzene (150 mL) and dry acetone (100 mL) was added aluminum z-propoxide (3.0 g, 14.7 mmol). The mixture, protected with a calcium chloride drying tube, was refluxed for 12 h. The reaction mixture was allowed to cool to ambient temperature and washed with 30% sulfuric acid (2 100 mL) and water until neutral. The organic extract was dried over anhydrous sodium sulfate and the solvent evaporated under reduced pressure. Fractional distillation of the product gave c/ s-a-decalone (15, 1.2 g, 80%) as a colorless oil (b.p. 116 °C (18 mmHg)) d2° 1.4939. 

Gas-chromatographic analysis involved diglycerol (15%, 2 meters, 50°C.) as stationary phase. From trans-Decalin, peaks were trans-9-hydroxy-decalin (t = 41), trans-a-decalone (t = 53), and trans-p-decalone (r = 74) from cw-Decalin they were ci5-a-decalone (t = 30), cis-/3-deca-lone (T = 55) and cw-9-hydroxydecalin (t = 100). Retention times are relative products were identified by comparison with authentic specimens, except for cw-a-decalone, where structure was assumed from retention time and analogy with the trans-series. Peak areas were obtained planimetrically. Relative product concentrations are given in Table I. 

Addition to carbonyl compounds yields branched high-molecular-weight alcohols. Functional reagents, inaccessible by conventional methods, can be prepared smoothly (Fig. 29). The Grignard reagent of 4-bromo-butan-2-one dioxolane thus prepared condenses with a decalone in 82% overall yield. ... 

The oxygen atom of ketones can be replaced by an isopropylidene group in two steps. This method allows synthesis of 4(14),7(ll)-selinadiene (LXXX) from a decalone derivative (LXXIX) (Posner et al., 1975b). 

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