Tris benzyl group

Boron trifluoride etherate, is also a good catalyst for this hydride transfer to chalcone. Unlike triphenylmethyl perchlorate, however, chalcone is able to enter Michael additions with the 1,5-diketone followed by eliminations leading to unexpected products, e.g., 3-benzyl-2,4,6-triphenylpyrylium from 2-carbethoxy-l,3,5-tri-phenylpentane-l,5-dione and chalcone the benzyl group originates from chalcone, the elimination product being ethyl benzoylacetate. ... 

KH/HMPT is also useful for selective 3-cleavage of tris(homoallylic) alcohols, as shown by a new synthesis of a-damascone (4). In general, l,l-dimethyl-2-pro-penyl and benzyl groups are cleaved more readily than a l-methyl-2-propenyl group,... 

The ketiniine 22 derived from benzyl trifluoromethyl ketone and 3-picolylamine. on the other hand, can be prepared.15 Its isomerization to aldimine 23 in triethylamine is complete in 58 hours at room temperature. Thus, the 3-picolyl group is much more reactive than the benzyl group in 14m. but less reactive than the 4-picolyl group. Various bases have been tried in the conversion of 22 into 23.15 Diethylamine is more effective than triethylamine, achieving complete isomerization in 35 hours. In contrast, the reaction catalyzed by DBU is exothermic and complete transformation into 23 can be achieved within a few minutes. 

In the case of tri-O-benzyl-D-glucal, entirely different chemistry is observed, with the initially formed cation 102 abstracting a hydride ion from the 0-6 benzyl group to give the 3-deoxy species 103. Intramolecular addition to C-2 affords 104 and the initially cleaved benzoyloxy group adds to C-l to give the unusual bicyclic 105 in 45% yield (Scheme 12).120... 

Considerably less is known about single ring complexes of the type Cp AnR3. According to Marks, thermal stability is a sensitive function of both the metal and the alkyl group. The synthetic approach of equation (63) has yielded only a few isolable compounds despite considerable effort. The X-ray stractures of the tris-benzyl compounds Cp Th(CH2C6H5)3 and Cp U(CH2C6H5)3 revealed multihapto metal-benzyl interactions. The latter may explain the stability of... 

Electron impact mass spectrometry studies of 1,3-di- and 1,2,3-tri-substituted imidazolines show ionization preferences depending on the substitution pattern (Scheme 23). Ions corresponding to R N were detected for all substrates (path 2). In 2-substituted 1,3-diarylimidazolidines, loss of substituents at C-2 ([M-R], path 3) is favored over the loss of hydrogen (path 4). In 1,2,3-trisubstituted compounds, azirinium ions (c, path 4A) were abundant, especially when R = aryl. 2-Phenylimidazolidines fragment to the characteristic tropylium ion (C7H7+, mjz 91). l-Aryl-3-benzylimidazolidines readily lose a benzyl group as radical or cation ([M-benzyl], path 1) <2000JHC57>. 

In the alpha compound the benzyl group replaces the hydroxyl hydrogen of hydroxyl amine while in the beta compound it replaces one of the amino hydrogens. There are also known two isomeric di-benzyl hydroxyl amines and one tri-benzyl hydroxyl amine. 

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