Decalone derivatives

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... 

Energy Differences (kcal/mol) Between Chair-Chair and Chair-Boat Conformations of m -2-Decalone Derivatives S3 to 58 (185)... 

The reductions of 1- and 12-keto steroids and their 1-decalone derivatives graphically illustrate the fact that dissolving metal reductions of ketones do not necessarily afford the more stable of a pair of epimeric alcohols. As a corollary, while the reduction of cyclic ketones is a synthetically useful procedure for the stereoselective preparation of secondary alcohols, it cannot be assumed that the thermodynamically stable alcohol will be the product which is obtained stereoselectively. 

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. ... 

Hydrindane derivatives, which bear a five-membered B ring (instead of a six-membered ring in the decalones derivatives) have also been examined for biohydroxylation by the fungus Rhizpous arrhizus192L All the hydroxylations observed now occur at position 3, to the a, 3-unsaturated ketone. This can be considered as... 

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). 

The enolates of 1- and 2-decalone derivatives provide further insights into the factors governing stereoselectivity in enolate alkylations. The l(9)-enolate of 1-decalone shows a preference for alkylation to give the cis ring junction. 

Sutherland and his co-workers have established that tetrasubstituted cyclohexane epoxides can fulfil a useful role as cationic cyclization initiators." Several alk-3-enyl-2,3-epoxy-3-methylcyclohex-2-enones, e.g. (177), have been successfully cyclized to decalone derivatives, e.g. (178), in good yield on treatment with Lewis acids, and the acetylenic epoxides (179) and (181) have been cyclized in excellent yields to the expected decalin (180) and hydrindane (182) derivatives respectively." ... 

Occidentalol is a eudesmane-type sesquiterpene isolated from the wood of Eastern white cedar Thuja occldentalis Linn.), and is characterized by the presence of a c/s-fused decalin system and a homoannular 1,3-diene unit in the molecule, an intriguing combination of functional groups rarely encountered in this class of natural products. Three related syntheses of occidentalol, all of which are based on hexahydronaphthalen-2-one intermediates have been reported, and utilize the carbonyl group for introduction of the diene chromophore in ring A 1-3,5 synthesis outlined below, utilizing a c/s-fused decalone derivative (A) illustrates several of the key features of these syntheses. 

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