Norbomadiene carrying

The study of alkene insertions in complexes containing diphosphine ligands turned out to be more complicated than the study of the CO insertion reactions [13], When one attempts to carry out insertion reactions on acetylpalladium complexes decarbonylation takes place. When the reaction is carried out under a pressure of CO the observed rate of alkene insertion depends on the CO pressure due to the competition between CO and ethene coordination. Also, after insertion of the alkene into the acetyl species (3-elimination occurs, except for norbomene or norbomadiene as the alkene. In this instance, as was already reported by Sen [8,27] a syn addition takes place and in this strained skeleton no (3-elimination can take place. Therefore most studies on the alkene insertion and isolation of the intermediates concern the insertion of norbomenes [21,32], The main product observed for norbomene insertion into an acetyl palladium bond is the exo species (see Figure 12.8). 

In an analogous reaction of (2) with norbomadiene, the tetracyclic adduct (116) is formed which on heating undergoes a retro Diels-Alder reaction with formation of the thiophene derivative (117). Further cycloaddition reactions of mesoionic 1,3-dithiolones have been carried out with cyclopentadiene, 1,3-cyclohexadiene and 1,5-cyclooctadiene (78CB3037). 

Booth et al. (M3) carried out the reaction of [Mn(CH3)(CO)j] with cyclo-pentadiene and found the reaction to be so slow that dimerization of cyclopentadiene occurred before reaction with [Mn(CH3)(CO)5] [Eq. (40)]. The reaction of [Mn(R)(CO)j] (R = CH3, Ph) with dicyclopentadiene directly, however, also gave a 1 2 adduct [Eq. (41)]. The reaction of [Mn(CH3)(CO)5] with norbomadiene, which gave a mixture of the 1 1 and 1 2 adducts, was also reported in this study. Other studies with different alkenes and alkynes gave the same type of products (M4,M5). 

Itoh and coworkers carried out tandem [2 - - 2 - - 2]/[4 - - 2] cycloadditions catalyzed by a ruthenium catalyst. The reaction of diyne 147 with excess norbomene 148 in the presence of ruthenium catalyst 153, for example, afforded 149. Adduct 150 either dissociated from the catalyst or reacted with anotoer equivalent of norbomene. In the latter case, a ruthenium catalyzed Diels-Alder reaction occurred, affording hexacyclic adduct 152 via 151 (equation 43). Compounds 150 and 152 were obtained in yields of 78% and 10%, respectively. Both cycloaddition reactions proceeded with complete stereoselectivity. When 1,6-heptadiyne was used instead of 147, only trace amounts of a cycloadduct were obtained. Replacing norbomene by norbomadiene, which was expected to result in polymer formation, did not afford any adduct at aU. 

N-acyldehydrodipeptides were readily prepared either by the condensation of N -acyldehydro-a-amino acids with a-amino acid esters or by the reaction of the azlactones of dehydro-a-amino acid with a-amino acid esters (eq. 1). Asymmetric hydrogenation of the N-acyldehydrodipeptides thus obtained (eq. 2) was carried out by using rhodium complexes with a variety of chiral diphosphines such as -Br-Phenyl-CAPP (3), Ph-CAPP (3), (-)BPPM (4), (+)BPPM (4), (-)DIOP ( ), (+)DIOP ( ), diPAMP (6), Chiraphos (7), Prophos (S), BPPFA (9) and CBZ-Phe-PPM (Fig. 1)(10). The chiral catalysts were prepared in situ from chiral diphosphine ligand with [Rh(NBD)2l -CIO4 (NBD = norbomadiene). Typical results are summarized in Tables I-V. 

The radical cation of (163) can be formed by electron transfer photochemistry and in methanol addition products are formed. A study of the photochemical reactivity of some novel 3-phenylnorbomadienes has been reported. Bichromo-phoric norbomadiene derivatives have also been synthesized and studied photo-chemically. A study of the photoisomerization of some norbomadienes has been carried out within the constrained environment of P-cyclodextrin. The bichromophoric system (164) undergoes intramolecular electron transfer by a through-bond mechanism on irradiation. The transfer is from the benzidine... 

Polynortricyclene forms by cationic polymerization of norbomadiene by a transamular polymerization. The reaction is best carried out below -100 C to prevent crosslinking. Two propagation paths are possible ... 

In this article, we focus the discussion on our investigations on [27t + 2n + 2ti] (homo Diels-Alder, HDA) and [2 i + 2 t] cycloaddition reactions of norbomadiene that were carried out during the past seven years. 

Two controversial hard insecticides are aldrin and dieldrin. [The Environmental Protection Agency (ERA) halted the use of these insecticides because of possible harmful side effects and because they are not biodegradable.] The commercial synthesis of aldrin began with hexachlorocyclopentadiene and norbomadiene. Dieldrin was synthesized from aldrin. Show how these syntheses might have been carried out. 

Syntheses of norbornenes and norbomadienes having Si-containing substituents as a rule were carried out by the above-mentioned Diels-Alder condensation of cyclopentadiene (or dicyclopentadiene) and Si-containing ethenes or ethynes [177]... 

Nishimura, I., Kameyama, A., and Nishikubo, X, Synthesis of self-photosensitizing polyesters carrying pendant norbomadiene (NBD) moieties andbenzophenone groups and their photochemical reactions. Macromolecules, 31, 27S9-2796,1998. 

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