Endo-Dicyclopentadiene

Figure 6. NMR spectrum of the sulfurated products of endo-dicyclopentadiene (almost an equimolar mixture of cis-exo and trans addition products as shown) in CSe using TMS as internal standard...

Table 5-1. Comparison of the activation energies and specific rate constants for the bimolecular Diels-Alder cycloaddition reaction of cyclopentadiene giving endo-dicyclopentadiene in the gas phase and in solution at 20 °C [3, 33, 34],...

A typical procedure is provided by the oxidative cleavage of endo-dicyclopentadiene to the corresponding dialdehyde (Scheme 1). A solution of potassium permanganate (3.41 mmol) and tri-ethylbenzylammonium chloride (141 mmol) in dichloromethane (40 mL) was added dropwise to a solution of en o-dicyclopentadiene (2.27 mmol) in 20 mL of the same solvent maintained at 0-3 C. After the addition, which took 40-50 min, stirring was continued for an additional 30-40 min by which... 

The optically active isomers of endo-dicyclopentadiene have been obtained (460) by reaction of a-phenylethylamine with (methoxydi-cyclopentadiene)chloroplatinum(II) dimer, separation of the diastereo-isomcrs of the monomeric (CioHi20CH3)Pt(amine)Cl, and treatment of these with KCN. 

P-2 Nickel boride shows a remarkable ability to selectively hydrogenate the strained double bond of norbornene. Thus hydrogenation of 5-methylenenor-bornene (1) and of the endo-dicyclopentadiene (3) give essentially quantitative yields of the dihydro derivatives (2) and (4), respectively.8... 

Similar chemistry occurs with 1,5-cyclooctadiene and endo-dicyclopentadiene ... 

Surprisingly arylpalladium complexes generated from Na arylsulfinates and PdCl (with deinsertion of SO2) add to endo-dicyclopentadiene to form the exo-cis adduct . The aryl group may coordinate the Pd in the adduct to stabilize it ... 

Recently, the regioselectivity of nucleophilic attack on (endo-dicyclopentadiene-PdCl2) has been used to confirm theoretical predictions concerning the mode of olefin activation by transition metals. Calculations suggest that olefin activation can occur by a lateral slipping of the olefin away from the symmetrical h geometry. The carbon most distant from the metal develops a partial positive charge and is predicted to be the site of nucleophilic attack . 

Figure 7 Stern-Volmer plots of (a) the naphthalene-sensitized reaction of endo-dicyclopentadiene (O) and (b) the fluorescence of naphthalene in the presence of benzene ( )...

Fig. 11.4 Variation of yield of oligomers ( ) and polymers (O) with time in the ROMP of endo-dicyclopentadiene catalyzed by ReCl5/Me4Sn (1/1) in CCI4 at 50°C [M]o = 3 M...

The ready accessibility of only one coordination (via loss of CO) site about copper makes Cu[HB(pz)3]CO (Figure 2) potentially attractive as a specific sensitizer for photorearrangements of olefins. For example, endo-dicyclopentadiene in the presence of Cu(03SCF3) undergoes virtually exclusive photodimerization (Reaction 7, path i), presumably via prior formation of a 2 1 olefin Cu(I) complex (17). Since the analogous bis-olefin complex involving the Cu[HB(pz)3] moiety is sterically improbable, the most likely photoprocess is internal cyclization (Reaction 7, path ii). Preliminary studies in our laboratory indicate that Cu[HB-(pz)3]CO sensitizes the NBD-to-Q conversion (Reaction 3) with respectable quantum efficiency (21). 

Several additions have been kinetically studied by more than one research group, but most of them were studied in solution and different workers used different solvents, so that the published data cannot be compared for reproducibility, Such a difficulty does not arise for reactions in the gas and in the pure liquid phases. Two popular Diels-Alder reactions, the dimerisation of cyclopentadiene to endo-dicyclopentadiene and that of butadiene to 4-vinyl-cyclohexene are suitable for a comparison of experimental results. Rate coefficients from 8 different sources for the former reaction in the pure liquid phase at various temperatures (in the range where comparison is possible) are given in Table 2. The coefficients are all extrapolated to zero time, as both secondary reactions and variation of the environment during the reaction cause a drift in the observed values of k. Rate coefficients for butadiene dimerisation in the gas phase, from different sources, are collected in Table 3. In this case also the temperature range has been limited to that where comparison is possible. In both Tables 2 and 3 activation parameters, as given by the authors (unless otherwise indicated) are also listed. 

Katsube and Matsui [23] achieved a synthesies of (la) by a related sequence starting from (11b) and Hoffman—La Roche chemists [24] have described a route based on (11c). In an approach by a Reckitt and Colman team [25], the endo-dicyclopentadiene (15) was cleaved to the dialdehyde (16) and thence transformed via a second cleavage and epimerisation to afford the aldehyde (10b). 

The importance of precoordination is also evident in the CuOTf-promoted27T + 2 r photocycloaddition of endo-dicyclopentadiene. This diene forms an isolable 2 1 complex with CuOTf involving evo-monodentate coordination with the 8,9-C=C bond of two molecules of diene. Consequently, intermolecular 2 r + 27r photocycloaddition involving exo addition to the 8,9-C=C bond is strongly favored over intramolecular reaction between the 8,9- and 3,4-C=C bonds (eq 11). This contrasts with the intramolecular photocycloaddition that is promoted by high energy triplet sensitizers. ... 

The synthesis of (+ )-sesquifenchene (450) and of ( )-epi-P-santalene (451) from the common intermediate (449), derived from endo-dicyclopentadiene, has been detailed. Conversion of (449) into the precursor of (450) makes use of the skeletal rearrangement that occurs during solvolysis of active 2-norbornyl esters. In a synthesis of (-H )-hinesol (452) and 10-epi-(-l-)-hinesol, interesting use has been made of a fragmentation reaction.The tosyl derivative (453), which was obtained in several steps from ( —)-P-pinene, was converted into the spiro[4,5]decane (455) on treatment with sodium hydride in DMSO the essential stereoelectronic changes are summarized in the intermediate (454). 

The trisubstituted titanacycles 8 and 10, derived from the reaction of 1 with two equivalents of cyclopentene and with one equivalent of endo-dicyclopentadiene respectively, can react with AlMea and give the corresponding methyl-bridged complexes. The yield can not be quantitative as the reaction temperature... 

The simple gold(I) dicarbonyl cation has been structurally characterised in the form of [Au(CO)2]SbF6. An endo-dicyclopentadiene-gold(I) chloride complex... 

A new complex formed between endo-dicyclopentadiene and gold(I) chloride has been prepared by a substitution reaction in dichloromethane, whereby carbon monoxide in dissolved [AuCl(CO)] has been displaced by the endo-dicyclopentadiene ligand/-The first example of the use of the Hofmann/Fischer reagent cyclopentadienylindium(I) for carbon-carbon bond formation and the demonstration of a one-pot tandem addition/intramolecular Diels Alder reaction in aqueous media have been reported/ The synthesis and solid-state structures of two new beryllocenes have been reported. These are [Be(CsMe4H)2] and [Be(C5Mes)2], which are obtained in the metathesis reactions of the potassium salts of the cyclopentadienes with beryllium dichloride, the former at room temperature and the latter at elevated (115 °C) temperature. ... 

Figurski, G. Von Weber, U. Einige physikalische Eigenschaften der cyclischen Kohlenwasserstoffe 1-Vinylcyclohexen-3 5-Vinyl-2.2.1-hepten-2 4,7,8,9-Tetrahydroinden imd endo-Dicyclopentadien die freie Exzessenthalpie ihrer binaeren Mischungen bei 80 bzw. 90.deg.C. Wiss. Z. Wilhelm-Pieck-Univ. Rostock, Math.-Naturwiss. Reihe 1976, 25(10), 1071-1074.

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