Bicyclo octanes 1,5-cyclooctadienes

The fused cyclobutenes prefer a path which leads to disallowed cis, cis cyclic diene. Thus bicyclo-octane(IV) opens at 230°-260°C to give cis, cis 1,3 cyclooctadiene and not cis-trans diene. 

A. 2-(TricHoromethyl)bicyclo[3.3.0 octane. To a 5-1. three-necked flask equipped with a mechanical stirrer, a reflux condenser, and a thermometer are added 325 g. (3.0 moles) of cw,m-l,5-cyclooctadiene (Note 1), 3 1. of chloroform (Note 2),... 

This two step procedure appears to be by far the most convenient one for preparing exo-ch-bicyclo[3 3 0]octane-2-car-boxylic acid from the readily available starting materials The first step of the procedure is also illustrative of the method of obtaining 2-substituted bicyclo[3 3 Ojoctanes4,6 from cis cn-1,5-cyclooctadiene. 

A bicyclic peroxide was isolated in 1.8% yield by HPLC of the bromodemercuration product, and was identified as a single diastereoisomer of 2,4-dibromo-6,7-dioxa-bicyclo[3,2.1]octane 57 with the iransjrans- or cis,cis-configuration. By analogy with the cyclooctadiene reactions, formation of the other two diastereoisomers of 57 can be expected, but although additional peroxides with similar HPLC characteristics were detected, they were not identified. Thus the presence of [2.2.2]-compounds cannot be ruled out, and no comment can be made on the regioselectivity of the dioxabicyclization. 

The thermolysis of ladderanes has been studied in detail (Scheme 1). On heating, bicyclo[2.2.0]hexane and its derivatives exhibit skeletal inversion and cleavage to 1,5-hexadiene derivatives.26 The thermolysis of anti- and yyft-tricyclo[4.2.0.02,5]octanes and their derivatives gives cis,cis- and cis, trans-1,5-cyclooctadienes, cis- and trans-1,2-divinylcy clobutanes, and 4-vinylcyclohexene as ring-opening products.27-29 Furthermore, syn-tricyclo-[4.2.0.02,5]octane isomerizes to aw//-tricyclo[4.2.0.02,5]octane.29c,d The thermodynamic parameters and the reaction mechanisms for these thermal reactions have been discussed. 

Trichloroacetyl fluoride, 45, 6 2-(Trichloromethyl)bicyclo[3.3.0]octane, from reaction of chloroform and cib,o i-l,5-cyclooctadiene, 47,10 hydrolysis with phosphoric acid to c.ro-m-bicyclo[3.3.0]octane-2-carboxylic acid, 47, 11 1,1,3-Trichloro- -nonane, 46,104 Tricyclo[2.2.1,02 6]heptan-3-ol, 46,... 

Primare Amine konnen sich unter Verbriickung an beide C,C-Doppelbindungcn von cyc-lischen Divinyl-ketonen addieren. Auf diese Weise erhalt man aus 3-Oxo-l,4-cyclohepta-dien bzw. 3-Oxo-l,4-cyclooctadien mit Methylamin, Ethylamin oder Benzylamin N-sub-stituierte 3-Oxo-8-aza-bicycIo[3.2.1]octane bzw. 3-Oxo-9-aza-bicyclo[3.3.1 ] nonane1 ... 

Diethyl malonate or ethyl cyanoacetate 187 afforded bicyclo[3.3.0]octane derivatives 188 in a tandem radical addition/transannular 5-exo cyclization sequence with cyclooctadiene 131 in 76 and 78% yield, respectively [275]. (4-Pentenyl)arenes were employed in a similar tandem radical addition/radical... 

Uemura and co-workers have demonstrated that reaction of 1,5-cyclooctadiene with antimony pentachloride in carbon tetrachloride at —20 ° leads to a mixture of the epimeric dichloro bicyclo[3.2.1 ]octanes 49 and 50.83 Through dehydrochlorination and Ag+-promoted ionization, a bicyclo[3.3.0]octenyl acetate was produced (Scheme 16). 

However, the methoxy palladation adduct of 1,5-cyclooctadiene gave one of the two epimers of 2-ewdo-methoxy-6-halo-cij-bicyclo(3.3.0)-octane and 2,6-ewdo,ewdo-dimethoxy-m-bicyclo(3.3.0)octane. The... 

C-C bond formations. Iron(III) perchlorate effects cyclization of 1,5-cyclooctadienes to bicyclo[3.3.0]octane derivatives and oxidative dimerization of naphthalenes. Thiols are also oxidized to give disulfides. 

Chloroform and an organic peroxide. Dowbenko has described an interesting radical-induced cycloaddition of chloroform to cij,cw-l,5-cyclooctadiene (I) to produce a 2-(trichloromethyl)bicyclo[3.3.0]octane (2) and hydrolysis of the latter to exo-cis-bicyclof3.3.0]octane-2-carboxylic acid (3). In the procedure cited the oxidant is... 

Table 1. Formation of Cyclooctenes and Cyclooctadienes from Mono- and Dihalobicyclo[5.1.0]octanes and Bicyclo[5.1.0]octenes...

The electrophilic additions of formic and acetic acids to l,5-dimethyl-l,5-cyclooctadiene yielded mainly - 5yu-8-substituted-l,5-dimethylbicyclo[3.2.1]octanes (equation 10) via parallel jr-cyclization and subsequent Wagner-Meerwein (W-M) type rearrangement. Cross TT-cyclization leading to bicyclo[3.3.0]octane derivatives, which were the major adducts in other electrophilic additions to unsubstituted l,5-cyclooctadiene2 22 comprised only a minor route. This different behavior has been interpreted (equation 11) in terms of a significantly larger stability of the tertiary carbocation II than that of the secondary ion in, both ions being the two potential intermediates derived from I by a parallel and a cross jr-cyclization, respectively. 

Cyclooctadiene undergoes a transannular reaction to form a bicyclo[5.1.0]octane system 1. The initiating electrophile and terminating nucleophile are trans-located in the product19. 

Cyclooctadiene has been stereoselectively converted to bicyclo[3.3.0]octane-2,6-diol in the presence of catalytic amounts of Pd(OAc)2 and Pb(OAc)4/HOAc96. 

The product of the palladation reaction exists as an active intermediate and cannot be isolated in general. However, the product of palladation was isolated as a stable compound in the reaction of cyclooctadiene palladium complex with carbanions such as malonate or alcoholate. Further reaction of the complex with base to give bicyclo (6,1,0) nonene and bicyclo (3,3,0) octane systems was reported by Takahashi and Tsuji 108>. The reactions are understood as intra-and intermolecular nucleophilic addition reactions. 

Transannular carbocyclization in the reaction of cis,cis-l,5-cyclooctadiene yields a mixture of three diastereomers of 2,6-diacetoxy-cw-bicyclo[3.3.0]octane, a useful precursor of cis-bicyclo[3.3.0]octane-2,6-dione (eq 1). ... 

Another way to obtain bicyclic compounds is to use free radical cycloaddition to 1,5-cyclodienes. As discussed in Section V.2.A (Scheme 15), in order to observe bicyclic compounds one must not use good transfer reagents. Thus, with cis,cis-l,5-cyclooctadiene as the substrate, the reaction is not only regioselective but also highly stereoselective toward the cw-bicyclo[3.3.0]-octane. Furthermore, the X (and Y) substituent would be in the exo... 

The first example of a reactiont of a carbon nucleophile with an olefin dates back to 1965 when Tsuji and Takahashi discovered that cyclooctadiene (COD) treated with PdCl2 afforded a stable complex 1 (Scheme 1). When this complex was treated with active methylene compounds under basic conditions a new complex 2 with both 77- and (7-Pd—C bonds were formed. Cyclization to the diethyl bicyclo[6.1.0]non-4-ene-9,9-dicarboxylate 3 then occurred readily under the basic conditions. When 1 equiv of the active methylene compound was added to complex 2, the tetraethyl bicyclo[3.3.0]octane-2,6-dimalonale 4 was formed by a transannulation reaction (Scheme 1). ... 

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