Aryl compounds syntheses

The reaction of isatin cr-chloride (160a) with electron-rich aryl compounds, in the presence of a Lewis acid, gives indolone salts (161) from which the indolones (162) can be liberated on treatment with base.49, 108, 109 The reaction of 160a with various amines, under these conditions, has been reported108 to give the unstable indolones (163) although later attempts to repeat the synthesis were unsuccessful.49... 

Friedel-Crafts coupling of an aromatic compound with an activated glycosyl donor is a classic, standard method for C-aryl glycoside synthesis [1,2]. Early interests were primarily centered at C-nucleoside synthesis, so that data were accumulated for the ribofuranosyl series with degradable aromatics to construct the nucleic base (Scheme 2) [5]. Equation (1)... 

In this chapter we will restrict our discussion of organometallic compounds to the alkyl and aryl compounds of magnesium and lithium, and the sodium and potassium salts of 1-alkynes. These substances normally are derived directly or indirectly from organohalogen compounds and are used very widely in organic synthesis. Organometallic compounds of transition metals and of boron are discussed in Chapters 11 and 31. 

Calcium has received some application in organic synthesis similar to that of magnesium alkyl and aryl compounds, CaRa, have been prepared, and it seems likely that many of the magnesium syntheses, already mentioned, could be accomplished by the use of calcium. 

Chopa, A.B., Lockhart, M.T. and Silbestri, G. (2002) Synthesis of bis-(trimethylstannyl)aryl compounds via an SRN1 mechanism with the intermediacy of monosubstitution products. Organometallics, 21, 5874-5878. 

A general method for the synthesis of Cp2TiR (R = alkyl, aryl) compounds consists of the reaction between [Cp2Tid]2 and a Grignard or organolithium reagent most of the Ti111 compounds have been synthesized in this manner.97... 

Another commercial aldehyde synthesis is the catalytic dehydrogenation of primary alcohols at high temperature in the presence of a copper or a copper-chromite catalyst. Although there are several other synthetic processes employed, these tend to be smaller scale reactions. For example, acyl halides can be reduced to the aldehyde (Rosemnund reaction) using a palladium-on-barium sulfate catalyst. Formylation of aryl compounds, similar to hydrofomiylation, using HCN and HQ (Gatterman reaction) or carbon monoxide and HQ (Gatterman-Koch reaction) can be used to produce aromatic aldehydes. 

The synthesis of iridium(lll) alkyl and aryl compounds via nucleophilic displacement is straightforward starting from a suitable L3lrX3 complex with X most commonly being chloride. Chatt and Shaw carried out early work on the syntheses of iridium(III) alkyl complexes showing that fac[lrMe3(PR3)3] (69) could be formed by reaction between... 

As in the Grignard reaction we may use any aliphatic aldehyde, ketone, ester or acid chloride, or an aryl compound of the same type and also, we may use either alkyl magnesium halides or aryl magnesium halides the synthesis makes possible the preparation of practically any desired secondary or tertiary alcohol either aliphatic or aromatic. Also if formaldehyde, in the form of its polymer, tri-oxy methylene, is used in the second reaction we will obtain primary alcohols. In the third reaction formic acid esters yield secondary instead of tertiary alcohols. These syntheses of alcohols by the Grignard reaction give us an idea of its importance in synthetic work. 

Cyclopentadienone is an elusive compound that has been sought for many years but with little success. Molecular orbital calculations predict that it should be highly reactive, and so it is it exists only as the dimer. The tetraphenyl derivative of this compound is to be synthesized in this experiment. This derivative is stable, and reacts readily with dienophiles. It is used not only for the synthesis of highly aromatic, highly arylated compounds, but also for examination of the mechanism of the Diels-Alder reaction itself. Tetraphenylcyclopentadienone has been carefully studied by means of molecular orbital methods in attempts to understand its unusual reactivity, color, and dipole moment. In Chapter 48 this highly reactive molecule is used to trap the fleeting benzyne to form tetraphenylnaphthalene. Indeed, this reaction constitutes evidence that benzyne does exist. 

Temperature is another important parameter that can improve the yield of nucleophilic substitution by suppressing the competitive reactions. Interestingly, low temperature can be used to selectively make mixed alkyl or aryl compounds [Eq. (47) 95]. This can be an effective one-pot synthesis to make a chiral, albeit racemic, phosphine. 

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