Rrans-Decalone

However, as already stated [12] this is probably unnecessary, since in the basic medium in which the cyclisation takes place the rrans-decalone with no angular methyl group would be in equilibrium with the corresponding cii-decalone. Even in the less favoured case, the equilibrium would shift to the cis-isomer since this is the only isomer which can cyclise to twistanone. Should this be the case, then the stereochemical control in preparing the starting decalone would be unnecessary and the synthesis would be greatly simplified. 

When the molar ratio MejAl ketone was approximately unity, ketones (134)— (137) gave 96% axial alcohols 2,2,6-trimethylcyclohexanone, with an axial methyl, gave 88% axial alcohol. Axial attack decreased in the substituent sequence 4-t-butyl-, 2-methyl-, ds-2,6-dimethyl. The decrease with successive introduction of 2-and 6-equatorial methyl groups was paralleled by a decrease in axial attack with decreased flexibility of the ring system in the sequence 2-methyl-, ds-2-methyl-4-t-butyl-cyclohexanones, and rrans-decalone. With cis-2,6-dimethyl- and 2,2,6-tri-methyl-cyclohexanones, at a MejAl ketone ratio of 2 1, the percentage of axial alcohol... 

The morpholine enamine of rrans-2-decalone exists as a 1 4 mixture of A - and A -isomers DAD reacts with the former by equatorial attack and the latter by axial attack (Scheme 177). In contrast, less electrophilic alkenes, such as -nitrostyrene and phenyl vinyl ketone, react only with the A -isomer at C-3 by axial attack (see Section III.B), unless sterically impeded. 

Methylcyclopropene, 178 l-Methyl-rrans-2-decalone, 179 cis-9-Methyl-l-decalone, 179, 180 frans9Methyl-l -decalone, 179—180 Methyl desisopropyl dehydroabietate, 180-... 

Trimethylamine, 87 Trimethylamine oxide, 114, 309-310 Tiimethyl borate, 296, 310 Trimethylchlorosilane, 310-312, 316 1,1,1O-Trimethyl-rrans-2-decalone, 179 Trimethylenemethane, 101 Trimethylironlithium, 312-313 Trimethylmanganeselithium, 112 Trimethylolpropane, 144 Trimethyl orthoformate, 103, 313... 

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