M-allyl

Electron delocalization m allylic carbocations can be indicated using a dashed line to show the sharing of a pair of rr electrons by the three carbons The structural formula IS completed by placing a positive charge above the dashed line or by adding partial pos itive charges to the carbons at the end of the allylic system... 

Molecular orbitals are useful tools for identifying reactive sites m a molecule For exam pie the positive charge m allyl cation is delocalized over the two terminal carbon atoms and both atoms can act as electron acceptors This is normally shown using two reso nance structures but a more compact way to see this is to look at the shape of the ion s LUMO (the LUMO is a molecule s electron acceptor orbital) Allyl cation s LUMO appears as four surfaces Two surfaces are positioned near each of the terminal carbon atoms and they identify allyl cation s electron acceptor sites... 

Figure 49.2. Catalytic oxidation of the allylic alcohols 11, 16 and 17 with FePcCli -S to the corresponding a, 5-unsaturated ketones. Reaction conditions 0.125 M allylic alcohol in acetone, 0.5 % mol FePcClis-S, 1.3 mmol of dry TBHP, 40T, 3 h.

Figure 4.88 Metal-carbon bond NBOs in M(allyl) complexes for (a) edge (Tl-c and (b) middle aIrC bonds of Ir(r 3-C3H5), and (c) the crAuC bond of Autri -CjHs ) cf. Fig. 4.87.

Scheme 21 Radical [3 + 2] annulation involving M-allyl-W-chlorotosylamide...

In a study of 64 men employed in the production of chlorinated compounds [time-weighted average exposures, < 1 ppm [4.5 mg/m l 1,3-dichloropropene, 3.1 mg/m allyl chloride and 3.8 mg/m epichlorohydrin], sperm counts and percentages of normal sperm were similar in the study group and among 63 controls. The volunteer participation rate for the study group was 64% (lARC, 1986). 

A series of M-allyl sulfamates, phosphoramides, and phosphorimidates was prepared to explore the possibility of O- N rearrangements via the intermediacy of the contact alkene radical cation/anion pair, followed by 5-exo-trigonal radical cyclizations (Fig. 4) [142],... 

In the presence of GaCl3, allylsilanes add to simple terminal alkynes and silylated alkynes to give m-allylation products.213 A stepwise mechanism including formation and ar-addition of an allylgallium species is plausible for this allylation. 

With the same length of the tether, the replacement of a butenyl lactate by M allyl 3-hydroxy propanoate 127 led to comparable or lower diastereoselectivitiJ (Scheme 29). J... 

The reactions of the structurally related M-allyl acethydrazides 185 gave similar results [100]. As indicated in Scheme 28, at - 30 °C the cyclization afforded the six-membered 1,3,4-oxadiazines 186 and at 20 °C gave the five-membered M-acetyl pyrazolidines 187. 

Toshima, K, Ishizuka, T, Matsuo, G, Nakata, M, Allyl C-glycosidations of totally unprotected glycals and allyltrimethylsilane with trimethylsilyl trifluoromethanesulfonate (TMSOTf), Tetrahedron Lett., 35, 5673-5676, 1994. 

Methyl-4-(6-phenyl-l-hexenyl) carbamate (5 grams) in 400 milliliters of 40 per cent sodium hydroxide solution was refluxed for two hours. The reaction mixture was then steam distilled and the distillate extracted several times with ether, The ether extracts were dried over anhydrous sodium sulfate, filtered, and the solvent removed by evaporation. The resulting product, a p/m-allyl-gamma-phenylpropylamine, was converted to the hydrochloride addition salt by the addition of ethereal hydrogen chloride. 

The unsaturated cationic titanium allyl compound [Gp 2Ti(allyl)]+BPh4- is prepared by oxidation of the titanium(m) allyl complex Cp 2Ti(allyl) with a ferrocenium cation. Nucleophilic addition to the cationic unit proceeds regioselectively to the central allylic position. Reaction with benzyl Grignard or the enolate of propiophe-none affords the corresponding titanacyclobutane complexes (Scheme 513).1305... 

Lone pair Z Base and Adjacent CH Complex Metal Hydride MH4- Organo- metallic R-M Allylic Z-C=C Simple Pi Bonds C=C CsC Aromatics 0... 

Sources SinkJJ Lone pair Nu Base bi and adjacent CH Metal hydride MH4 Orgsmometal. R-M Allylic a C=C-Z Simple pi bonds C=C Aromatic ArH... 

Although there are two more hydrogen atoms in the system L M + allyl than are present in a metallacyclobutadiene, the operative word in this problem is formal. Here, you are asked to interact only the orbitals from the metal and the allyl system that would produce the corresponding orbitals in the metallacyclobutadiene. 

Without any inhibitor Saturated carbon monoxide Saturated ethylene 0.10 M Allyl alcohol Saturated acetylene 0.10 M Propargyl alcohol... 

Grafting group 10 diallyl complexes, [M(allyl)2] (M 206,207 208,209 pj) 210 silica have been reported to yield... 

SiO)M(allyl)] as evidenced by the evolution of 1 propene per grafted metal (Scheme 60). 

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