Allyl aromatization

Base-catalyzed Isomerization of Allylic Aromatic Compounds [68]... 

Figure 4b. 200 MHz H-NMR spectrum of o,w-di(chloro allyl) aromatic polyether sulfone (PSU) from Scheme 4 (M 1,930, CDCI3, IMS).

Scheldt and co-workers have also illustrated the oxidation of activated alcohols to esters [132], Oxidations of alcohols such as 260 provide the electrophile (acyl donor) for a nucleophilic alcohol 261. Esters 262 are derived from propargylic, allylic, aromatic, and hetero-aromatic substrates (Table 20). The nucleophilic alcohol scope includes MeOH, n-BuOH, f-BuOH, 2,2,2-trichloroethanol, 2-methoxyethanol, and 2-(trimethylsilyl) ethanol. 

By far the most generally useful synthetic application of allyltributyltin is in the complementary set of transition metal- and radical-mediated substitution reactions. When the halide substrates are benzylic, allylic, aromatic or acyl, transition metal catalysis is usually the method of choice for allyl transfer from tin to carbon. When the halide (or halide equivalent) substrate is aliphatic or alicyclic, radical chain conditions are appropriate, as g-hydrogen elimination is generally not a problem in these cases. 

Allylation of arenes and alcohols. Allyltrimethylsilane and some related al-lyltrialkylmetal reagents of Sn and Ge in combination with iodosylbenzene (1 equiv.) activated by BF3 etherate (0.25-1 equiv.) allylate aromatics in CH2C12 at -30° to 25°. Under these conditions alcohols are converted into allyl ethers, even though iodosylbenzene is a known oxidant for alcohols.4... 

Palladium-Catalyzed Carboalkylations of Allylic, Aromatic, and Vinylic Halides... 

The TT-allyl-cr-arylpalladi urn-phosphine complexes have been of particular interest in the study of the mechanism of their reductive elimination to yield allylated aromatics.148 149 Their preparation can be achieved by the addition of a triarylthallium or arylzinc halide to the corresponding allylpalladium phos-phino halides (equation 34). 

A short review in Chinese covers Friedel-Crafts reactions of alkenyl halides with aromatic hydrocarbons.49 High yields of the allylated aromatic products have been... 

The para Rearrangement (Table III). If both ortho positions of an allyl aromatic ether are blocked, the allyl group migrates to the para position. If both ortho positions and the para position are occupied, complex decomposition ensues, but the allyl group never goes to the... 

The reaction was explained by a nucleophilic attack of the allylmetal on the electron-deficient iodine atom. The resulting allyliodine(III) intermediate (135) then reacts with the aromatic substrate to afford a tricoordinate allyliodine(III) compound (136), which undergoes ligand coupling to give the allylated aromatic derivative. (Scheme 5.16)... 

Ni/C-catalysed cross-couplings en route to allylated aromatics toluene-4-sulfonic acid 2-(3,7,l 1,15,19,23,27,31,35,39-decamethyltetraconta-... 

Ni/C-CATALYSED CROSS-COUPLINGS EN ROUTE TO ALLYLATED AROMATICS TOLUENE-4-SULFONIC ACID... 

Besides styrene, many other alkenyl and allyl aromatics can be hydroformylated with chirally modified transition metal catalysts. Depending on the substitution pattern, problems of regio- and stereoselectivity here are similar to those of styrene or aliphatic alkenes. The results are compiled in Table 5. 

We have further examined the reactions of thiolato-bridged diruthenium complexes with other unsaturated organic substrates. When the cationic Ru complex 4 is treated with cinnamyl alcohol in p-xylene, the allylated aromatic compound 18 is obtained in good yield (Equation 6). We assume a Tc-allyl intermediate because the reaction using l-phenylprop-2-en-l-ol gives, instead of cinnamyl alcohol, the same product 18 however, the detailed reaction mechanism is still obscure. This novel allylation reaction is halogen-free, and may replace the conventional Friedel-Crafts alkylation. 

Arylpalladium salts, prepared in situ, react with allylic halides to give allyl-aromatic derivatives 76>. 

It should be noted that allylic, aromatic, and vinylic Grignard reagents do not form adducts [23]. 

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