Trans hydrindane

In contrast, when /f-D-mannopyranosylamine reacts with thiophosgene, only the cis bicyclic thionocarbamate is formed and the transient isothiocyanate cannot be detected (Scheme 4). The different behaviour of the cis and trans hydrindane-type systems can be explained by the strain in the ring fusion for a trans species. 

It is worthwhile to compare the stability differences of the analogous hydrindanes and decalins. In both cases, the Gibbs standard free energy differences favor the trans isomers, by 1.3 kJ mol" in the hydrindanes and by about 10 kJ mol in the decalins (94MI3). This direction of the difference is in contrast with that found for the 1,3-heteroanalogs of cis- and trans-hydrindane. 

Condensation of the vinyl alcohol (54) with 2-ethylcyclopentane-l,3-dione je j to the expected product from which B-noroestradiol was ultimately obtained.19 Of particular conformational interest is that the double bond in one of the intermediates (55) was not isomerized by acid to the A9(11)-position despite the fact that the compound is a trans-hydrindane. The compound (56), prepared from m-methoxyphenylethylmagnesium bromide and the corresponding cis-hydrindanedione, undergoes dehydration but not cyclization on treatment with... 

Przezdziecka, A., Stepanenko, W., Wicha, J. Catalytic enantioselective annulation using phenylsulfanylmethyl vinyl ketone. An approach to trans-hydrindane building blocks for ent-vitamin D3 synthesis. Tetrahedron Asymmetry 999, 10,1589-1598. 

Introduction of the cyclopropane moiety with the correct stereochemistry in the cyclopen tenone subunit was successful in creating an angular methyl group at the C/D junction of the trans-hydrindane ring system of paspalicine, an indole diterpene mould metabolite. ... 

Another route to trans-hydrindanes starts with the stereoselective construction of two adjacent trans chains via Claisen rearrangements426 427. 

Standard depictions for steroids, such as those in Scheme 1, overlook the three-dimensional nature of the molecule. The structures in Scheme 2 represent the stereochemical arrangement implicit in the more customary formulas. The junction between rings B and C and also that between rings C and D involve transoid stereochemistry. It is of note in passing that the latter in fact comprises a disfavored trans hydrindane fusion. The ring junction between rings A and B is also transoid but can in selected cases assume a cisoid configuration (2-2). Note further that the stereochemical... 

Radical cyclization to trans-hydrindanes. Although 1,5-hcxadicnyl radicals generally cyclizc to a five-membered ring, the radical formed from the vinyl bromide 1 [Bu3SnH-B(C2H5)3] cyclizes to a tram-hydrindanc 2 selectively, possibly via radicals a and b. The presence of an angular methyl group docs not prevent a similar... 

A trans hydrindane system was also accessible by trapping the radical intermediate resulting from the first cyclization with an allyl group with net trans addition across the double bond establishing the desired trans ring junction (Scheme 10-57). 

The INOC reaction also plays a crucial role in the synthesis of the trans-hydrindane derivative 322, a potential intermediate for the synthesis of the C2-symmetric pentacychc alkaloid papuamine 319 (1997CC495). Nitroal-kene 321 was prepared from racemic anhydride 320 in a few steps. Nitrile oxide formation was then carried out in situ by the reaction of 321 with PhNCO which resulted in cyclization to afford the racemic irares-hydrin-dane 322 (Scheme 58). 

Consistent with the observations detailed above, annelation of the vinyl bromide 49 under identical conditions (1.1 equiv of KH, 5 mol % Pd(dppe), THF, 55 °C) also proceeded with diastereoselectivity. Bicycle 50 was obtained as a single isomer with a trans-hydrindane system in 70% yield (Scheme 22). ° ... 

It is believed that the transition state (88) is responsible for the observed stereochemistry, and that bases utilizing a metal which bonds ti tly to oxygen favour (88) hence the selectivity of the zirconium base. This approach to trans-hydrindanes has been applied to a short stereoselective synthesis of adreno-sterone. A mixture of cis- and rran -hydrindanes is obtained by treating 1,2-divinylcyclohexane with a titanocene hydride derivative. ... 

To arrive at the trans-hydrindane 459 the aUyl radical is introduced this way and consequently estabHshes the trans orientation of the hydrogen atoms at Cj and Cj. 

Several new acids related to spiculoic add A were found subsequently in the species Plakortis zyggompha harvested in Martinique. These contain all the original skeleton of trans-hydrindan-2-one and a detailed structural study has revealed the definitive stereochemistry of all compounds of this family (Berrue et al, 2005a, 2007). AH of these polyketide-type derivatives are moderately cytotoxic or antimycobacterial. 

Saha, A. and Bhattacharjya, A. (1997) Novel nitrile oxide cycloaddition approach towards papuamine-stereoselective synthesis of a potentially useful trans-hydrindane intermediate. Chem. Common., 495-496. 

Ishizaki, M., Hara, Y, Kojima, S., and Hoshino, O. (1999) Studies on a total synthesis of plakotenin Synthesis of optically active trans-hydrindanes by diastereoselective asymmetric intramolecular Diels— Alder reaction. Heterocycles, 50, 779-790. 

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