Tricyclo deca-3,5,7-triene

Chelate complexes of the type [PdX2(diene)] (X = Cl, Br) are readily formed by the dienes hexa-1,5-diene (124), bicyclo 2,2,lJhepta-2,5-diene (1, 7) tricyclo[4,2,2,0]-deca-triene and -diene derivatives (10), cyclo-octa-1,5-diene and dicyclopentadiene, but not dipentene (43). These may be converted to complexes of the types [Pd2X2(dieneOR)2] and [PdCl(dieneOR)-(amine)] (R = alkyl) (43), and their properties indicate that they have similar structures to the platinum complexes (XXXI) and (XXXIII). 

The reaction of oxepin with dimethyl 5-oxo-2,3-diphenylcyclopenta-l,3-diene-l,4-dicarboxy-late takes a different course. Two products 7 and 8 can be isolated, 7 is the [4 + 2] adduct of the cyclopentadienone across the central C-C double bond of the oxepin, the other, 8, is thought to be a [4+6] cycloadduct across the triene system of the oxepin.237 In boiling benzene, the [4 + 2] adduct 7 undergoes no cycloreversion, but rearranges to the tricyclo[5.3.02,4]deca-5,8-dien-10-one system.237 The [4+6] adduct, however, is stable under thermal conditions. 

A special method, with only two examples, starts from 1,2,4-triazines.20 21 Diels-Alder reaction with the strained dienophile dimethyl tricyclo[4.2.2.02,5]deca-3,7,9-triene-7,8-dicarboxylate (14) is followed by an elimination of nitrogen via a retro-Diels-Alder process. The formed product, however, cannot be isolated, but reacts via another retro-Diels-Alder reaction and an electro-cyclic reaction to provide the azocine derivative 15. The sequence order of the reactions is not clear, but both pathways lead to the same product. 

The synthesis of fUido-tricyclo[4.4.0.02 5]deca-3,8-dien-7,10-dione and verification of its endo-configuration has been reported earlier.3 This adduet is a useful starting material for the syntheses of tetracyclo-[5.3.0.02 6.03 10]deca-4,8-diene,s tricyclo[4.4.0.02 5]deca-3,7,9-triene,6 cis, syn, cjs-tricyclo[5.3.0.02,6]deca-4,8-dien-3,10-dione,7 and 4-oxahexa-cyclo[5.4.0.02 6.03 10.05 9.08,11]undecane.a... 

Durham route, the metathesis polymerization of 7,8-bis(trifluoromethyl)tricyclo[4.2.2.0]deca-3,7,9-triene gives a high-molecular weight soluble precursor polymer that is thermally converted to polyacetylene (equation 19.6). The precursor polymer is soluble in common organic liquids and easily purified by reprecipitation. The end product can be aligned giving a more compact material with bulk densities on the order of 1.05 —1.1 g/cm. ... 

A clean eiectrocyclic ring opening occurred at mild temperatures with the strained tricy-clo[4.3.0.07-9]nona-2,4-diene (3a) and tricyclo[4.4.0.02 5]deca-7,9-diene (3b) to give cycloocta-1,3,5-triene derivatives 4.182... 

The 11 NMR spectrum of 2,6-dibromo-8-thiatricyclo[2.2.1.23 s]heptane 15 has been reported <1996RCB2393, 2000RJ0794>. The chemical shifts in the 111 NMR spectrum have been assigned to all protons of 15. H NMR spectra of angular benzobisthietes 4,9-dithia-tricyclo[6.2.0.02 s]deca-l(8),2(5),6-triene 16 and 3,10-dithia-tricy-clo[6.2.0.0z s]deca-l,5,7-triene 17 were recorded <1998TL9639>. The chemical shifts for both isomers are similar. For example, the singlets at 4.16 and 4.27 ppm for 16 and 17, respectively, correspond to four CH2 protons. 

As an alternative, copolymerization of alkynes bearing bulky substituents with TCDTF6 (7,8-bis(trifluoromethyl)tricyclo [4.2.2.0 ]deca-3,7,9-triene) was carried out. In the course of this copolymerization, usually referred to as the Durham Route [86-89], the Feast-monomer was introduced into the polymer main chain and subsequently converted into three unsubstituted, conjugated double bonds via a thermally-induced retro-Diels Alder reaction (Scheme 3) [53]. 

The cycloaddition of 3. M,2,4-triazole-3,5(4f/)-diones to the norbornene-fused cyclopentadi-enes (dehydroisocyclopentadienes or tricyclo[5.2.1.02-6]deca-2,5,8-trienes) usually proceeds from below the plane of the cyclopentadiene to give the adducts 36 with the synsesquinctrbor-nene structure, but loss of stereocontrol is observed due to geminal disubstitution at C-4. 

Two laboratories - have reported the synthesis of isobullvaicne (7, tricyclo-[5.3.0.0 °]deca-3,5.,8-triene) in the same way from lithium cyclononatetraenide (6) by treatment with methylene chloride and n-butyllithium at a low temperature. The major product is isobullvalene (7), accompanied by the flOjannulene (8) and cij-9,10-... 

A 1 2 CT complex of bis(f -tricyclo[5.2.1.0 ]deca-2,5,8-trien-6-yl)iron(ii) 1 (depicted below) with TCNQ has recently been reported [55]. The solid state structure is characterized by segregated stacks of donor and acceptor ions, in which the TCNQ columns form a zig-zag array of equally spaced molecules. This type of arrangement is in principle well suited for the purpose of electrical conductivity, but in this case no measurements thereof have been carried out. 

Dimethyl maleate, dimethyl fumarate, (Z)- and (Z)-dibenzoylethylene, maleic anhydride, methyl cinnamate, styrene, methylstyrene, norbornenes and norbornadiene, cyclopentene, tetramethyl- and tetracyanoethylene, and dimethyl tricyclo [4.2.2.0 ]deca-3,7,9-triene-7,8-dicarboxylate react similarly with 2,5-diaryl-l,3-dithiolium-4-olates. In many cases the stereochemistry of the products has been elucidated. 

Various bi- and oligocyclic ring systems, such as norcaradiene (1 bicyclo[4.1.0]hepta-2,4-diene), bicyclo[6.1.0]nona-2,4,6-triene (2), bullvalene (3 tricyclo[3.3.2.0 ]deca-3,6,9-triene), semibul-Ivalene (4 tricyclo[3.3.0" ]octa-2,7-diene), barbaralone (5 tricyclo[3.3.1.0 ]nona-3,6-dien-10-one) and many other systems containing divinylcyclopropane subunits, exhibit interesting transition metal mediated reaction pathways leading to new carbon skeletons. ... 

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