Alkylate yield

Electrochemical oxidation of disulfides and trapping of intermediately formed sulfmates by alkylation yields sulfones in good yields494. 

The mechanism of anionic polymerization of styrene and its derivatives is well known and documented, and does not require reviewing. Polymerization initiated in hydrocarbon solvents by lithium alkyls yields dimeric dormant polymers, (P, Li)2, in equilibrium with the active monomeric chains, P, Li, i.e. 

To form the process model, regression analysis was carried out. The alkylate yield x4 was a function of the olefin feed xx and the external isobutane-to-olefin ratio jc8. The relationship determined by nonlinear regression holding the reactor temperatures between 80-90°F and the reactor acid strength by weight percent at 85-93 was... 

The isobutane makeup x5 was determined by a volumetric reactor balance. The alkylate yield x4 equals the olefin feed xx plus the isobutane makeup x5 less shrinkage. The volumetric shrinkage can be expressed as 0.22 volume per volume of alkylate yield so that... 

The acid strength by weight percent x6 could be derived from an equation that expressed the acid addition rate x3 as a function of the alkylate yield 4, the acid dilution factor Xg, and the acid strength by weight percent x6 (the addition acid was assumed to have acid strength of 98%)... 

The motor octane number jc7 was a function of the external isobutane-to-olefin ratio jc8 and the acid strength by weight percent x6 (for the same reactor temperatures and acid strengths as for the alkylate yield x4)... 

Scheme 14 Cathodic reduction of aromatic esters to aromatic aldehydes X= H, alkyl, yields 0-70%.

Scheme 15 Cathodic Birch-type reduction of aliphatic esters to alcohols R alkyl, yields 95%.

Scheme 24 Cathodic alkylation of carboxylic acids to esters R alkyl, aryl, R alkyl, yields 24-96%.

Scheme 25 Cathodic reduction of activated aliphatic carboxylic acids to aldehydes (R alkyl, yields 70-82%) and ketones (R benzyl, yields 66- 72%).

Scheme 27 Cathodic reduction of amino acids in the presence of triphenylphosphine to amino aldehydes R alkyl, yields 81-84%.

Scheme 29 Cathodic reduction of ketones diols R aryl, R H, yields in general 45-100% alcohols R R alkyl, yields in general, 45-100%.

Scheme 33 Base catalyzed condensation of aldehydes by electrogenerated bases (EGB s) R alkyl, yields 72-77%, very high current efficiency.

Scheme 34 Cathodic cyclization of unsaturated ketones R alkyl, yields 75-98%.

Scheme 36 Intramolecular cathodic cyclization of ketones with aryl rings R alkyl, yields 21-74%.

Scheme 38 Cathodic intermolecular coupling of ketones with alkenes R R, R alkyl, yield 52-82%.

Scheme 41 Cathodic intermolecular coupling of ketones with vinyl ethoxy dimethylsilane R R alkyl, R H, alkyl, yields 62-79%.

The first clue to the existence of the SrnI mechanism came from product studies both in aliphatic and aromatic cases. It was noticed that in the reaction of benzyl and substituted benzyl chlorides with the 2-nitropropane anion, oxygen alkylation, yielding the oxime and then the aldehyde, occurs exclusively in the case of benzyl chloride and 3-nitrobenzyl chloride, whereas, with 4-nitrobenzyl chloride, the yield of aldehyde is only 6% and the carbon-alkylated (104) product is obtained in 92% yield (Kornblum, 1975). This was interpreted as the result of a competition between 8, 2 (O-alkylation) and S l (C-alkylation) reactions. In the aromatic case, it was observed that the reaction of 5- and 6-halopseudocumenes with KNHj in liquid ammonia (Kim and Bunnett, 1970) forms the 5- and 6-pseudocumi-dines in a ratio which is the same whether the starting compound is the 5- or 6-isomer in the case of the chloro- and bromo-derivatives, as expected from an aryne mechanism (Scheme 9), whereas much more non-rearranged... 

The first step in the peroxide-induced reaction is the decomposition of the peroxide to form a free radical. The oxygen-induced reaction may involve the intermediate formation of a peroxide or a free radical olefin-oxygen addition product. (In the case of thermal and photochemical reactions, the free radical may be formed by the opening up of the double bond or, more probably, by dissociation of a carbon-hydrogen bond in metal alkyl-induced reactions, decomposition of the metal alkyl yields alkyl radicals.)... 

R = secondary alkyl yield <25% no conversion for R = secondary alkyl and R = CH2CH20Me... 

The alkylation process is highly exothermic and proceeds through the formation of tertiary butyl carbocation species. Alkylate yields are usually quite high,... 

The intramolecular variant of ester enolate alkylations is a very useful ring-forming reaction. It can often be carried out under milder conditions than the corresponding intermolecular alkylation. Yields and diastereoselectivities are usually high. 

A camphor-based 3-acyl-2-oxazolidinone has also been used for diastereoselective alkylations66. The A-acylated auxiliary 18 is prepared in three steps from 7,7-dimethyl-2-oxobicy-clo[2.2.1]heptane-l-carboxylic acid (ketopinic acid, 17)67. Deprotonation by lithium diiso-propylamide in tetrahydrofuran at — 78 °C and subsequent alkylation with activated halides [(bromo- or (iodomethyl)benzene, 3-bromo- or 3-iodopropene] furnished moderate to good yields of alkylation products in high diastereomeric ratios (>97 3 by H NMR). With added hexamethylphosphoric triamide the alkylation yields are increased and bromoalkanes also give satisfactory yields. The diastereomeric ratios are, however, much lower (d.r. 70 30 to 85 15)67. 

Meta- Alkylation Yield d [ ]d Meth- Center Yield ... 

Unsymmetrical 3,6-dialkoxy-2,5-dihydropyrazines (e.g., 3 and 4), derived from L-valine and either glycine11 or alanine12, respectively, have been more extensively studied. These reagents are commercially available in both enantiomeric forms6. In general, considering diastereomeric excess, alkylation yield and hydrolysis, the best results are obtained with these unsymmetrical derivatives. 

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