Cis-decal

Irie and co-workers (37) have recently observed that the double Michael reaction of dimethyl acetone dicarboxylate on dienone 104 gave the cis decal-in product 106. This result indicates that intermediate 105 underwent a stereoelectronically controlled internal Michael addition to give 106. Without stereoelectronic control in the Michael reaction, there is no apparent reason to prevent the formation of the trans isomer 107. However, if this factor is taken into consideration, examination of molecular models indicates that it seems impossible to obtain isomer 107. 

The first precise evaluation of the anomeric effect was realized by Descotes and co-workers in 1968 (22). These authors have studied the acid catalyzed isomerization of the cis and trans bicyclic acetals and 6 and found that, at equilibrium, the mixture contains 575S ci and 43% trans at 80°C. The cis isomer is therefore more stable than the trans by 0.17 kcal/mol. The cis isomer has one (stabilizing) anomeric effect whereas the trans isomer 6 has none. Steric interactions in cis acetal were estimated tobel.65 kcal/mol (one gauche form of ji-butane, 0.85 kcal/mol and an OR group axial to cyclohexane, 0.8 kcal/mol). By subtracting an entropy factor (0.42 kcal/ mol at 80 C) caused by the fact that the cis acetal exists as a mixture of two conformations (cis decal in system), they arrived at a value of 1.4 kcal/mol for the anomeric effect. 

Mechanisms of the formation of the decal ins in the recovered solvent were based on their isotopic contents. The cis-Decalin-die had a greater protium content than the recovered Tetralin-di2-This suggested that hydrogen transfer from the coal to the tetralin is involved in the formation of cis-Decalin. 

The isotopic composition of the Decal ins in the spent solvents is indicative of the mechanisms of their formation. A total of 6 hydrogen atoms are added to the Tetralin to form Decal in. In E10, during the course of the experiment, the average protium concentration in the Tetralin increased from 2.3 to 21.3 atom % 1H. The protium content of 34 atom % 1H in the cis-Decalin was greater than the protium content in the Tetralin. Likewise in El9, the protium content in the Tetralin increased from 1.0 to 12.3 atom% H, while the cis contained 18.8 atom % 1H. This increase of pro-... 

An investigation of the isotopic composition of the Decal ins, which were formed as minor products in the donor solvent experiments, showed that cis-Decalin was formed preferentially. Its formation and its increased protiurn incorporation may have resulted from increased contact with the coal surface. Trans-Decal in contained less protiurn than the Tetralin, which suggests that most of the trans-Decalin was formed with deuterium from the Tetralin-di2 and deuterium gas. 

Figure 6 Dependence of the product distribution on conversion for H-Beta zeolites (filled), TT-Y-12 (open), Pt/IT-Beta zeolites (half-filled), and Pt/fl-Y-1 2 (open with dash). A) Trans-decal in ( , U, H, B), cis-decalin ( , O, , 0), Isomers (A, A, A, A), B) ROP ( , t>, t>, t>), CP ( , O, ), HP (, ...

The chemical (Gif system) and the electrochemical conversion (Gif-Orsay system) have been compared in the oxidation of six saturated hydrocarbons (cyclohexane, 3-ethylpentane, methylcyclopentane, cis- and traus-decalin and adamantane). The results obtained for pyridine, acetone and pyridine-acetone were similar for both systems. Total or partial replacement of pyridine for acetone affects the selectivity for the secondary position and lowers the ratio ketone secondary alcohol. The formation of the same ratio of cis- and traws-decal-9-ol from either cis- or trans-deca in indicates that tertiary alcohols result from a mechanism essentially radical in nature. The C /C ratio between 6.5 and 32.7 rules out a radical mechanism for the formation of ketones and secondary alcohols. Ratios of 0.14 and 0.4 were reported for radical-type oxidations of adamantane and cis-decalin. Partial replacement of pyridine by methanol, ethanol or f-propanol results in diminished yields and a lower selectivity. Acetone gives comparable yields however, the C /C ratio drops to 0.2-10.7. 

Cl 5H2ij02, (DL)-5a-Ethenyl-5/3-hydroxy-1, 1, 4a/3-tr imethyl-1, 4,4a,5,6,7,8,8aa-octahydronaphthalene-2(3H)-one, 46B, 145 Cl5H24O3, 9-Carbomethoxy-4,6,6 trimethyl-trans-decal-3-one, 40B, 159 C15H24O4, cis-1,1-Bismethoxycarbonyl-4a-methyl-decahydronaphthalene, 38B, 206... 

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