Cis hydrindane

A similar result was reported by Vandewalle 15°-151>. Irradiation of 1,2-bis(tn-methylsiloxy)cyclobutene and compounds (441) afforded compounds (442), which were reduced with LiAlH4 to give the endo alcohol (443). Treatment of the alcohol (443) with methanol for 24 hours would bring about silylether cleavage as well as unexpected direct oxidation of (443) to the cis-hydrindanes (444) in 50-70 % yield (Table 18)130). 

Procter employed a highly diastereoselective Sml2-mediated intramolecular 1,4-addition during studies on the synthesis of faurinone treatment of iodide 77 with Sml2 in THF-HMPA gave cis-hydrindane 78 in good yield (Scheme 5.51).84... 

Homopropargylzinc chloride, 388 D-Homosteroids, 53 Htlnig s base, 151 Hydrazine hydrate, 230 Hydrazinium acetate, 207 Hydrazobenzene, 206 cis-Hydrindanes, 45 Hydriodic acid, 199-200 Hydroalumination, 131, 133, 237-238 Hydrodeamination, 412 Hydrogen bromide, 200-201 Hydrogen chloride-Titanium(IV) chloride, 201... 

Cycloaddition to enones.1 The reagent undergoes photochemical cycloaddition to cyclopentenones and cyclohexenones to form cis-anii-cis-cyclondducls selectively. The products can be converted into cis-hydrindanes and cw-decalones. 

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. 

Both iodides 22a-e and triflate 24 can be converted to the corresponding cis-hydrindans by similar methods to those used for decalins once again Ag3P04 was found to be the most effective silver salt in the conversion of the former. Small... 

S. Siegel University of Arkansas) The stereochemical evidence shows that, for the reaction which controls the rate of the stereospecific addition of hydrogen, the geometry of the transition state is like the most stable conformation of the olefin. Very nearly the same geometry, however, should also pertain to the most stable conformation of a cyclohexane ring in which a pair of adjacent cis bonds are forced to be coplanar as in cis-hydrindane or better (0, 2, 4)-bicyclooctane. This latter geometry applies... 

H L M 2-Methyl-2-pentanol 1,4-dioxane Cis-Hydrindane Branched alcohols... 

Bicyclic and higher polycyclic alkanes exhibit much more complex MS fragmentation. Budzikiewic and coworkers caution that great prudence, even in the use of published spectra, must be exercised for comparison and identification purposes of polycyclic alkanes. As examples they show the mass spectrum of cis-hydrindane, in which m/e 95,96,81 are major fragments which can be assigned only in retrospect to the structure once known. However, given only the MS it will be impossible to reconstruct the structure of the molecule. 

In the cis-hydrindane synthesis it is the hydrogen radical that approaches from the convex side of the bicychc silylether intermediate 454 (see 454 ), thus generating the cis-ring juncture of457. 

Conjugate addition of the propargyl anion equivalent 8 to 1 proceeded with the expected >95 5 axial diastereoselectivity, to give the silyl enol ether 9. Exposure of the derived iodide 10 to catalytic [Ph PAujCl and AgBF induced smooth cyclization to the cis hydrindane 2. 

D. Since any reaction in which the 0 4 atom takes place in a configuration-ally unstable form (free radical, carbanion, carbonium ion) leads to the stable cis-hydrindan system of rings C and D, the only possibility for obtaining the natural trans-C/D linkage is the use of catalytic hydrogenation. 

To prepare efficiently the opposite isomers, that is, cis-hydrindanes and trans-decalins, the access to the Z-dienoaldehyde was required. We have found that such Z-dienoaldehyde is available by thermal decomposition of the secondary sugar allyltin (72 in Figure 10.22). Its reaction with Ph3P=CHC02Me followed by cyclization... 

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