Bicyclooctane

For a related diastereoselective route to spiro-fused bicyclooctanes, see refs 144-147. The construction of bicyclic compounds with a cis ring junction is also used in the formation of key intermediates, such as 5, for forskolin148 149 and vernolepin150,151, see also ref 152. 

As suggested by Roberts and Moreland many years ago (1953), the acidity constants of 4-substituted bicyclooctane-l-carboxylic acids provide a very suitable system for defining a field/induction parameter. In this rigid system the substituent X is held firmly in place and there is little possibility for mesomeric delocalization or polarization interactions between X and COOH (or COO-). Therefore, it can be assumed that X influences the deprotonation of COOH only through space (the field effect) and through intervening o-bonds. On this basis Taft (1956, p. 595) and Swain and Lupton (1968) were able to calculate values for o and crR. 

The a-sulfonyl carbanions can be trapped with a variety of electrophiles19. The method provides a synthetically useful synthon for a propylene 1,3-dipole. Reductive cleavage of the sulfone 28 thus prepared, with lithium phenanthrenide in THF, furnishes bicyclooctane 29 (equation 19)16. 

The bicyclooctane sulfite illustrated can be oxidized with Ru04 to the sulfate in 72% yield.[29] The mannopyranoside sulfate was obtained by means of Af,N -sulfonyldiimi-dazole (ImSO2Im).[30] A trifold cyclic sulfate was synthesized according to route b.t31]... 

DMBCOl), dimethylbicyclo[3.2.1]octanes (DMBC02), ethylsubstituted bicyclooctanes (EBCO) and trimethylbicycloheptanes (TMBCH). The last group consists of trimethylbicyclo[2.2.1]heptanes, trimethylbicyclo[3.1.1]heptanes and dimethylbicyclo[2.2.2]octanes. Some representative structures of the Iso groups are shown in Figure 2. Major cracking products (CP) were identified as cyclic hydrocarbons C5-C9 and isobutane. The main heavy products (HP) were methyl-and dimethyldecalins, or their isomers. No olefins and only traces of aromatics were found in the products. Detailed information about the product analysis is reported elsewhere (22). 

Aviram and Ratner s originally proposed D-a-A molecule (or Gedankenmolekiil ), 35 (Fig. 14), included the excellent donor TTF (27) and the excellent acceptor TCNQ (33), separated by a rigid bicyclooctane bridge [79]. This molecule was never made (and would likely not have made a good monolayer), but it was the impetus for the synthesis of many new candidate rectifiers. 

These effects can occur when the active site at which a measurable phenomenon occurs is in close proximity to the substituent. Among the many systems exhibiting direct steric effects are ortho-substituted benzenes, 1, cis-substituted ethylenes, 2, and the ortho- (1,2-, 2,1- and 2,3-) and peri- (1,8-) substituted naphthalenes, 3, 4, 5 and 6, respectively. Other examples are d.v-1,2-disubstiUited cyclopropanes, c/ s-2,3-disubstituted norbornanes and ci.s-2,3-disubstituted [2.2.2]-bicyclooctanes, 7, 8 and 9, respectively. Some systems generally do not show steric effects. Vicinally substituted systems such as disubstituted methanes, 10, and 1,1-disubstituted ethenes, 11, are examples, 2,3-Disubstituted heteroarenes with five-membered rings such as thiophenes and selenophenes... 

Diorganotin dichalcogenates can be prepared by the reaction of the dichlorides with H2S in the presence of triethylamine, or with Li2Se or Li2Te then, reaction in situ with a tetrachlorodisilane gives distannatetrachalcogena-bicyclooctanes (Equation (170)).513... 

An example of a compound having a preferred boat conformation is that of [2.2.2] bicyclooctane. This compound must necessarily exist as a boat because its cis-4 hydroxy cyclohexane-carboxylic acid easily forms lactose and the water elimination must proceed through the boat conformation. The trans isomer will not lactonize. 

An exchange quantity, S(,(tert/sec, sec, sec), not previously calculated, is found to be ca —59 kJmol-1 from this example. By comparison with other exchange quantities in Table 2 this value seems inaccurate26. However, we note that the cis/trans enthalpy difference of pyrrolizidine (ca 14 kJ mol-1 from Reference 25) is significantly less than the ca 26 kJmol-1 we deduce for bicyclooctane. This should not surprise us because trivalent nitrogen has been known to accommodate strain by partial or total planarization27. 

The long known132 electron donor-acceptor complexes between tertiary amines and carbon tetrahahdes are simple systems. Thus, l,4-diaza[2,2,2]bicyclooctane (DABCO) or quinuclidine afford solid complexes with carbon tetrabromide142. 

Data for the bicyclooctane system in 50% w/w Et0H-H20 are the basis for primary 07 values according to Charton109, calculated through equation 10no. 

Bicyclooctanes, isomerization paths of, 20 282 Bicycio (2.2.2)-2- octene, 20 269, 270 Bifimctional catalysts, ring closure, cyclization, 29 311-316 C5 cyclization, 29 311... 

The notation refers to the configuration at the junction of three cyclohexane rings with the bicyclo[2.2.2] octane skeleton. A prime indicates that the cyclohexane ring is oriented counterclockwise when viewed along the Cs-axis of bicyclooctane part otherwise the orientation is clockwise. 

The chemist can encode a structure in many ways and, provided the representation follows the above rules, each alphanumeric string will generate a proper connectivity file. For example, (c-c-c-cl-c-c-c-c2-), cl-c2" or (cl-c2-c-c-c-), cl-c-c-c-c2" are both proper representations of 3.3.0-bicyclooctane. lUPAC numbering can be followed or the numbering can be arbitrary. 

If the cyclic monomer does not have twofold symmetry, the inversion at a single caibon atom can produce optically active polymers, as in the case of the dioxa[3.2.1]bicyclooctane, 41 (85). 

The benzene ring in nematogens can be substituted by alicyclic rings such as cyclohexane, bicyclo (2.2.2) octane and cubane. This has led to the discovery of cyclohexane and bicyclooctane analogues of cyanobiphenyls. Substitutions of a benzene ring by cyclohexane or bicyclooctane has the effect of increasing Nl-... 

In contrast, bridgehead (i.e., tertiary) C—H bonds can be selectively oxidized to tertiary alcohols using chromic acid in acetic acid.112 Since the reactivity of these compounds depends on the ability of the bridgehead carbon to become sp2-hybridized, norbomane and bicyclooctanes are unreactive at the bridgehead positions. Adamantane, bicyclo[3.3.1]nonane, bicyclo[3.2.2]nonane, and bicyclo-[3.3.2]decane, in turn, afford the corresponding tertiary alcohols in 40-50% yields. 

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