G alkylation

An Index to types of reactions, e.g. alkylations, stereoselective reductions, cyclizations etc. and... 

The formation of g-alkyl-a,g-unsaturated esters by reaction of lithium dialkylcuprates or Grignard reagents in the presence of copper(I) iodide, with g-phenylthio-, > g-acetoxy-g-chloro-, and g-phosphoryloxy-a,g-unsaturated esters has been reported. The principal advantage of the enol phosphate method is the ease and efficiency with which these compounds may be prepared from g-keto esters. A wide variety of cyclic and acyclic g-alkyl-a,g-unsaturated esters has been synthesized from the corresponding g-keto esters. However, the method is limited to primary dialkylcuprates. Acyclic g-keto esters afford (Zl-enol phosphates which undergo stereoselective substitution with lithium dialkylcuprates with predominant retention of stereochemistry (usually > 85-98i )). It is essential that the cuprate coupling reaction of the acyclic enol phosphates be carried out at lower temperatures (-47 to -9a°C) to achieve high stereoselectivity. When combined with they-... 

Figure 4-13. Liquid-liquid heterogeneous tubular flow reaotor (e.g., alkylation of olefins and Isobutane). (Source J. M. Smith, Chemloal Engineering KInetlos, 3rd ed., McGraw-Hill, Inc., 1981.)...

Primary ( ) amines e.g. alkyl amines [1—3] lipid amines [4] a, co-diamines [5, 6] polyamines [6] alkanol amines [7] subst. anilines [8] aminoglycoside antibiotics [9, 10] biogenic amines [11] hydrazines... 

For the Birch reduction of mono-substituted aromatic substrates the substituents generally influence the course of the reduction process. Electron-donating substituents (e.g. alkyl or alkoxyl groups) lead to products with the substituent located at a double bond carbon center. The reduction of methoxybenzene (anisole) 7 yields 1-methoxycyclohexa-1,4-diene 8 ... 

Polythiophene [78] is a promising material for certain future electronic applications, due to its relatively high stability and processability in the substituted form [79-81]. Upon substitution, with e.g. alkyl side-chains [79, 80], polythiophene exhibit properties such as solvalochromism [82] and thermochromism [83]. Presently, a large variety of substituted polythiophenes with various band gaps exists (for example see Ref. [81 ]). 

The element specificity of atomic absorption spectrometry has also been used in conjunction with gas chromatography to separate and determine organo-metallic compounds of similar chemical composition, e.g. alkyl leads in petroleum here lead is determined by AAS for each compound as it passes from the gas chromatograph.75... 

The exchange of tert-butyl for a smaller group, e.g., alkyl or 4-methylpheny], causes a decrease in the induced diastereoselectivity70. If a prostereogenic aldehyde is used, in addition. the problem of simple diastereoselectivity arises and four diastereomeric products are... 

Peroxides N,N-Dimethyl-1,4-phenylenediamine (N,N-DPDD), N,N,N, N -tetra-methyl-l,4-phenylene-diamine (TPDD) Peroxides, e. g. alkyl hydroperoxides, oxidize N,N-DPDD to Wurster s red and TPDD to Wurster s blue. [17] [34]... 

Peroxides, e.g. alkyl hydroperoxides, oxidize N.N-DPDD to Wurster s red and TPDD to Worster s blue. 

The THF ligand of (Ti5-Mc4C5-SiMe2-N Bu)Crni(THF)Ph is only weakly bound, and dissociates in solution. Indeed, with sterically more demant g alkyl groups base-ftce five-coordinate alkyl con lexes, e.g. (n -Me4C5-SiMe2-N Bu)CrCH2SiMe3, could be pr ared. 

Experiment 2 Saturate distilled water with a rare gas and compare the intensity of the signal with that from air. The luminosity will be enhanced in the rare gas saturated solutions. For any gas atmosphere, add small amounts of volatile water-soluble solutes (e.g. alkyl series alcohols) and quantify the quenching of sonoluminescence as a function of both bulk quencher concentration and surface excess. Good correlation between the extent of quenching and the Gibbs surface excess should be observed. Explain the changes in sonoluminescence intensity when a rare gas atmosphere is used and the quenching of volatile solutes, in terms of simple thermodynamics. 

MCM-22 zeolite (IZA code MWW) presents a novel and original structure which is composed of two independent pore systems a 2-dimensional, sinusoidal, 10-ring intralayer channels system and an interlayer system with 12-ring supercages, accessible through 10-ring apertures [1], This unique pore structure of the aluminosilicate MCM-22 zeolites makes them interesting catalysts for a wide variety of acid-catalyzed reactions, e.g. alkylation of aromatics [2],... 

Ordering of a PU film presents some restrictions on the chemical nature of the molecules. The molecules will typically need to be made amphiphilic by attaching either pendant nonpolar (e.g., alkyl) groups to yield a hydrophobic end, or pendant polar (e.g., carboxylic acid) or even ionic (e.g., carboxylate anion) groups to make a hydrophilic end, complicating the synthetic task. Further, the pendant groups may have a cross section that is not well matched with the size of the electroactive... 

Being electron-rich it is a very reactive intermediate and forms the basis of many important organic synthesis. It can combine with a great variety of electrophiles e.g., alkyl halides and ketones and can form compounds having carbon-carbon bonds in high yields. 

It has been noted that electron-withdrawing substituents (e.g., halogens) on the carbon bearing the proton deshield the proton, while electron releasing substituents (e.g. alkyl group) shield the protons. 

---