Bicyclo- -nonane derivative

The potential of Fischer carbene complexes in the construction of complex structures from simple starting materials is nicely reflected in the next example. Thus, the reaction of alkenylcarbene complexes of chromium and tungsten with cyclopentanone and cyclohexanone enamines allows the di-astereo- and enantioselective synthesis of functionalised bicyclo[3.2.1]octane and bicyclo[3.3.1]nonane derivatives [12] (Scheme 44). The mechanism of this transformation is initiated by a 1,4-addition of the C -enamine to the alkenylcarbene complex. Further 1,2-addition of the of the newly formed enamine to the carbene carbon leads to a metalate intermediate which can... 

Two types of synthesis of this skeleton are reported depending on the positions of the sulfur introduced either at the bridge or at the bridgehead the former has been studied by Stetter s research group189-191 and the latter by Klages and Schmidt192 starting from bicyclo[3.3.1]nonane derivatives and cyclohexane derivatives, respectively. 

The mercuration-demercuration reaction of cw,cw-l,5-cyclooctadiene (3) has been widely studied in order to get some insight into the synthesis of 9-oxa and 9-azabicyclo-nonane derivatives. However, the results of the reaction have often been the subject of some controversy since the ratio of the two isomeric bicyclo[3.3.1]- [199 and 201] and [4.2.1]- [198 and 200] nonanes, after reduction (equation 166), strongly depended on the reaction conditions of the mercuration step168,169. 

In the case of McycKc systems (133—140) there are not yet enough data available for a detailed discussion to be given. The barriers obtained for the bicyclo [2.2.2]octane (133, 134) and the bicyclo[3.3.1]nonane (139, 140) compounds are in the range expected for the corresponding mono-cyclic systems. In the case of the bicyclo[3.2.2]nonane derivatives 135 and 136 the inversion barriers are larger than in the seven-membered ring compounds 127 and 128. 

Table 3. / -Chiral Ketones. Esters and Nitriles by Alkylation of x-Halo Ketones. Esters and Nitriles via 9-Alkyl-9-bora-bicyclo[3.3.1]nonane Derived from Prostereogenic Olefins22...

Initially the main PBDs isolated from floral resins of Clusia spp. showed to be bicyclo-[3.3.1]-nonane derivatives but a new study demonstrated the presence of several SBDs in these sources. Structures of weddellianone A (24) and B (25), lanceolatone (26) and hilarianone (27) were established on spectroscopic evidences of their methyl derivatives obtained after treatment of fresh floral resins with diazomethane [20], All the structures were represented with a 1,3,5-triketone system because of the treatment before mentioned don t facilitate the determination of the exact structures. On the other hand, many natural SBDs have shown to have methoxyl groups in their structures and then in the methyl derivatives above mentioned is not possible to establish the origin of the methoxyl groups certainly. 

De Oliveira et al. have published three main studies about chemical composition of Clusia s floral resins [18-20]. They have treated the floral resins with diazomethane in order to facilitate the separation of the major components. The first two works led to postulate the existence of the following PBDs in Clusia spp grandone (22), clusianone, nemorosone, hydro xynemorosone, 7-epinemorosone and nemorosone II. Except grandone all of them showed to be bicyclo - [3.3.1]-nonane derivatives. 

Extensive phytochemical studies developed with H. sampsonii led to the isolation of a family of caged PBDs named sampsoniones A-J (97-106) [51]. Many of them exhibited complex arrangements that were firmly established on the basis of spectroscopic evidences. Authors have suggested a very interesting biosynthetic via in which the same precursor for all these compounds, a bicyclo-[3.3.1]-nonane derivative, has been considered. Sampsoniones C-J showed three unconjugated carbonyls (5 203-207) similar to plukenetiones A and B isolated from C. plukenetii. Sampsoniones K-M have been also isolated but they were mentioned when PBDs with a bicyclo-[3.3.1]-nonane were considered. 

Also some bicyclo-[3.3.1]-nonane derivatives have shown antibacterial activity against MRSA. 

Some PBDs have shown cytotoxic activity. The SBDs vismiaguianones B, D and E, cudraphenones A-D and the bicyclo-[3.3.1]-nonane derivatives ochrocarpinones A-C, guttiferones A, E and G, xanthochymol possess this biological activity. 

Ochrocarpinones A-C (85-87), three bicyclo-[3.3.1]-nonane derivatives isolated from the bark of Ochrocarpos punctatus, were tested for cytotoxicity against A2780 ovarian cancer cells [14], All compounds were... 

For bicyclo[3,3,l]nonane derivatives which are unsubstituted at positions 3 and 7, it has been shown in several cases that chair-chair conformations are preferred, although the cyclohexane rings are distinctly flattened with valence-angle increases (cc. 4°) beyond ideal tetrahedral values. However, derivatives with bulky endo substituents at positions 3 or 7 may adopt boat-chair conformations. Thus for 9-benzoyl-3a-bromo-9-azabicyclo[3,3,l]-nonan-2-one (74) and for the 2-hydroxy-analogue, it has been argued... 

Hyperflorin, an antibiotic isolated from St. John s wort Hypericum perforatum L.), has been found on the basis of chemical and spectroscopic evidence to possess structure (639). ° A review on the conformational analysis of bicyclo[3,3,l]nonanes has appeared,and the conformations of l,5-disubstituted-3,7-dimethyIenebicyclo-[3,3,l]nonane derivatives have been shown, on the basis of lanthanide-induced n.m.r. shifts, to be predominantly in the double-chair form. In a notable paper that contains a wealth of information pertinent to adamantane synthesis, it has been reported that bicyclo[3,3,l]nonane-3,7-dicarboxylic acid, its dimethyl ester, and various derivatives exist mainly in the chair-boat conformation. The synthetic entry to these systems is illustrated for the above diester (643) in which the starting point is adamantanone (640) thus, ring expansion with diazomethane followed by SeOj oxidation gave the a-diketone (641) which was cleaved with periodate to give the diacid (642). Esterification using diazomethane gave (643) which exists, as does the diacid, as... 

Two novel routes to triethylborane have been reported. Irradiation of bromoethane and aluminium powder with ultrasound gives ethyl aluminium sesquibromide which on treatment with triethoxyborane gives triethylborane in good yields and a laser initiated gas phase reaction between diborane and ethene gives yields of upto 91%. Allylic boranes have been prepared from allylpotassiiim derivatives and chloroboranes. Hydrolysis leads to the Isomerised olefin and the technique has been used to transform (+)-a-pinene into (+)-3-pinene. Condensation reactions between allylboranes and acetylenes have been developed into a convenient method for the synthesis of bicyclo[3.3.l]nonane derivatives. Mainly linear alkyl derivatives of 9-BBN have been synthesised from the, reaction of iron carbonyls and the organoborane in a Fischer-Tropsch type reaction. ... 

Suggest an alternative bicyclo[3.3.1]nonane derivative that might be used to connect the carbons marked by asterisks in structure 6. Suggest tactics that will transform your proposed intermediate into twistane. (Unnatural Products-7)... 

An interesting approach to carbobicyclic polyhydroxylated compounds was proposed by Jarosz.43 It was based on a Lewis acid transformation of sugar allyltins 82 into dieno-aldehydes 83 with the fi-geometry across the internal double bond exclusively. The Wittig-type reaction of 83 afforded a triene, which underwent cyclization under high pressure, providing derivatives of bicyclo[4.3.0]nonane 84. Alternatively, dienoaldehyde 83 was converted into the phosphonate 85, which afforded the bicyclo[4.4.0]-decene derivatives (86) upon reaction with an aldehyde and simultaneous cyclization of the resulting triene.43 (Fig. 29). 

Studies by the submitters have indicated that the procedure reported here is the preferred method for the preparation of bicyclo[3.2.1]octan-3-one. It employs readily available, inexpensive reagents, and the overall yield is good. In addition, the method can be used for the synthesis of the difficultly accessible next higher homologues of bicyclo[2.2.2]oct-2-ene as well as for derivatives of norbornene. Bicyclo[3.2.2]nonan-3-one and l-methylbicyclo[3.2.1]octan-3-one have been prepared by a similar route6 in 60% and 47% yields, respectively (based on adduct). However, the preferred procedure for the formation of the dichlorocarbene adduct of bicyclo[2.2.2]oct-2-ene is that of Seyferth using phenyltrichloromethylmercury. Even in this case the overall yield is moderate (37%). 

In another approach 145, dibromocarbene was added to ( + )-cyclononadiene 127 to give (after reduction of the outside adduct) ( + )-trans-bicyclo[7.1.0]decane 132). From the dextrorotatory enantiomer of the above-mentioned dibromo-derivative 128, ( + )-trans-bicyclo[6,1.0]nonane 129) was accessible. Comparison of the chiroptical properties of (+)-129 and (+)-132 led to the conclusion that 127 had the (+)(/ )(axial) chirality145) in agreement with the results reported above 144). 

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