Ethene-cyclopentene

Deprotonation of N-methylpiperidine Al-oxide with LDA in THF at — 78°C takes place regioselectively on the least crowded methyl carbon to generate azomethine ylide 122 (8SJOC2910). Ylide 122 is again highly reactive toward nonactivated olefins such as ethene, cyclopentene, styrene, (E)- and (Z)-stilbene, and ( )-)S-methoxystyrene. 

Jerschow, A. Ernst, E. Hermann, W. Muller, N. Nuclear magnetic resonance evidence for a new microstructure in ethene-cyclopentene copolymers. Macromolecules 1995,28,7095-7099. 

The first metallocene-based COC material was synthesized from ethene and cyclo-pentene [218]. While homopolymerization of cyclopentene results in 1,3-enchainment of the monomer units [219], isolated cyclopentene units are incorporated into the ethene-cyclopentene copolymer chain by 1,2-insertion. Ethylene is able to compensate the steric hindrance at the ot-carbon of the growing chain after and before the insertion of cyclopentene [220]. 

Computer Project 5-2, The result for hydrogenation of cyclopentene differs from that foi ethene by an amount that is well outside the expected error foi MM calculations. Suggest a reason for this. 

Dimethyl-1-cyclohexyl-1-trimethylsiloxy-ethene (191) gives by means of methyllithium/ethylbromide in dimethoxyethane (DME) 1-cyclohexyl-2,2-dimethyl-1-butanone (297)133 Dimerizations occur when substances such as 1-trimethylsiloxy-styrene (192) or 1-trimethylsiloxy-l-cyclopentene (195) are treated with silver oxide/ DMSO to afford l,5-diphenyl-2,5-butadione (198) and 2,2 -dicyclopentanonyl (199)l34 respectively. Under the catalytic influence of Cu2+ ions, 192 plus ben-zenesulfonyl chloride yield phenyl-(l-phenyl-l-ethanone-2-yl)sulfone (200)l3 ... 

Cyclopenten l-(4-Methyl-piperazi-no)- E15/1, 609 (Keton + Amin) Ethen 1,1-Dipyrrolidino- VII/4,... 

Bicyclo 4.1.0]heptan 7-Trimethyl-silylcarbonyl- E17b, 1393 (7-Br/7-SiR3 — 7-H/7-CO—SiR3) Cyclohexan trans-2-Hydroxy-1-(trimethylsilyl-ethinyl)- E19d, 146 (sp-CH - C - Li/Oxiran) Cyclopenten 2-Ethyl-4-methylen-l-trimethylsilyl- E17c, 2251 (Methylen-cyclo propan + In) Ethen l-(l-Cyclohexenyl)- -trimethylsilyloxy- E1S/1, 441 (Keton 4- RjSi—O —S02 —R) Furan 2-Methyl-5-propyl-3-trimethylsilyl- E18, 674 (In-Hydromagnesier./+ R —CN)... 

Cyclopenten l-(4-Methoxy-phenyl)-E17c, 2542 (1-Ar — 1 -cyclopropyl-ethen/A)... 

The use of silica gel surfaces to modify photoprocesses continues to be of interest. The present report deals with photoaddition of alkenes to the steroidal enone (44).It is presumed that, in the adsorbed state on silica gel, the steroid will present the normally hindered side, i.e., the g-face is attacked by the alkene and the a-face is adsorbed on to the gel. The photoadditions were compared with those carried out in methanol. Thus with allene the two photoproducts (45) and (46) were obtained in 90 and 10% yields, respectively, at -78 °C in methanol, while on silica gel, both at -78 °C and at ambient temperature, the same two products were obtained in 46 and 53% yield. Similar results were obtained using ethene and cyclopentene. The photocycloaddition of ethyne and propyne to progesterone and testosterone in solution yields the cycloadducts (47) and (48), with a preference for the former mode of addition being observed. These results are in conflict with those of de Mayo and co-workers. ... 

The photochemical addition of ethene at 0°C in methylene chloride to the enedione (77) affords a high yield of the adduct (78). This was converted to the monochloro derivative (79) which also undergoes photoaddition of ethene to yield the Z> adduct (80). This on elimination of HCl yielded the quinol (81) which can be oxidised to the quinone (82). Cycloaddition of alkenes (cyclopentene, cyclohexene, and cycloheptene) has been carried out to the same enedione (77) to yield the adducts (83). lyoda et al. have also described a convenient synthesis of the bicyclo-octanediones(84) by a photochemical addition of alkenes to the enedione (77). The adducts (84) can be reduced by zinc in acetic acid to the desired products. Cycloaddition of ethyne to the same enedione followed by reduction affords the bicyclooctanes (85). The photoaddition of alkenes to the dibromo-enedione (86) is also effective and yields, after reduction, the adducts (87). 

The second methoxy species was found to function as a methylating agent. Injection of a pulse of benzene for example at 250°C into ZSM-5 previously exposed to methanol or dimethylether causes a decrease in the concentration of the second methoxy species and the appearance of toluene as a product downstream from the cell (benzene alone does not react over ZSM-5 at this temperature). Similar methylation was observed with ethene (forming propene). With other alkenes the results were less clearcut, since these formed oligomerization products in the absence of methoxy species, but a decrease in the infrared bands of the second methoxy species could still be detected when propene, cyclopentene and 1-hexene were injected into zeolites pretreated with methanol or dimethylether. 

Ethene (Ethylene) Cyclopentene have double bonds, . (e) Ethyne (Acetylene) has a triple bond Ethylene oxide heterocyclic (f)... 

In addition to ethene and (Z)-but-2-ene the following alkenes have been used as dienophiles cyclopentene, cyclohexene, cycloheptene 386 cyclooctene, bicyclo[2.2.1]hept-2-ene 387 hexa-1,5-diene, cycloocta-1,5-diene. cyclododeca-l,5,9-triene 388 -391 and bicycIo[2.2.1]hepta-2,5-di-... 

CPE = cyclopentene CHX = cyclohexene 1,4-CHX = cyclohexa-1,4-diene 2,4,6-Cg = octa-2,4,6-triene. The small molecules formed, such as ethene or propene, are not listed. 

One of the features of olefin copolymerization kinetics is the effect of comonomer on the rate of ethene or propene polymerization during ethene/a-olefin or propene/ a-olefin copolymerization, i.e., the so-called comonomer effect (CEF). The rate enhancement of ethene or propene polymerization in the presence of a comonomer is observed for conventional ZN catalysts [80, 113-123] and for homogeneous [124-133] and supported metallocenes [134—136] and post-metallocenes catalysts [137-140]. The increase in activity was remarked in the presence of such comonomers as propene, 2-methylpropene, 1-butene, 3-methylbutene,4-methylpentene-l, 1-hexene, l-octene,l-decene, cyclopentene, styrene, and dienes. 

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