Friedel-Crafts reaction reductive

Nowadays much less catalyst is needed. This is particularly important in large scale syntheses as of the intermediate needed by Merck16 for the drug intermediate 79. The starting material is ketone 75 easily made by a Friedel-Crafts reaction. Reduction using only 0.5% CBS catalyst 60 gave alcohol 76 of 98.9% ee. Even with only 0.1% 60, the ee of the product 76 was still 94.2%. 

Benzilic acid rearrangement Benzoin reaction (condensation) Blanc chloromethylation reaction Bouveault-Blanc reduction Bucherer hydantoin synthesis Bucherer reaction Cannizzaro reaction Claisen aldoi condensation Claisen condensation Claisen-Schmidt reaction. Clemmensen reduction Darzens glycidic ester condensation Diazoamino-aminoazo rearrangement Dieckmann reaction Diels-Alder reaction Doebner reaction Erlenmeyer azlactone synthesis Fischer indole synthesis Fischer-Speior esterification Friedel-Crafts reaction... 

Several methods are available to supplement the phenol alkylations described above. Primary alkylphenols can be produced using the more traditional Friedel-Crafts reaction. Thus an -butylphenol can be synthesized direcdy from a butyl haUde, phenol, and mild Lewis acid catalyst. Alternatively, butyryl chloride can be used to acylate phenol producing a butyrophenone. Reduction with hydrazine (a Wolff-Kishner reduction) generates butylphenol. 

Beyer synthesis, 2, 474 electrolytic oxidation, 2, 325 7r-electron density calculations, 2, 316 1-electron reduction, 2, 282, 283 electrophilic halogenation, 2, 49 electrophilic substitution, 2, 49 Emmert reaction, 2, 276 food preservative, 1,411 free radical acylation, 2, 298 free radical alkylation, 2, 45, 295 free radical amidation, 2, 299 free radical arylation, 2, 295 Friedel-Crafts reactions, 2, 208 Friedlander synthesis, 2, 70, 443 fluorination, 2, 199 halogenation, 2, 40 hydrogenation, 2, 45, 284-285, 327 hydrogen-deuterium exchange, 2, 196, 286 hydroxylation, 2, 325 iodination, 2, 202, 320 ionization constants, 2, 172 IR spectra, 2, 18 lithiation, 2, 267... 

The synthesis of deoxybenzoin from phenacetyl chloride and benzene by the Friedel-Crafts reaction has been described. For symmetrically substituted deoxybenzoins, direct reduction of the readily accessible benzoin is a more convenient method. Reduction of benzoin by zinc dust and acetic acid, and by hydrochloric acid and granulated tin or amalgamated powdered tin has been reported. The present method is based on a publication of the authors. ... 

Thiophenethiols are prepared by reduction of the sulfonyl chlorides or, more conveniently, by the reaction of Grignard rea-gents or thienyllithium compounds with sulfur. They have also been obtained by cleavage or thienyl alkyl sulfides with sodium in liquid ammonia. 3-Thiophenethiol is a by-product in the commercial thiophene synthesis. Thiophenethiols have recently also been prepared by a synthesis involving Friedel-Crafts reaction of 2,4-dinitrobenzenesulfenyl chloride with thiophenes, followed by basic cleavage of the resulting sulfide. ... 

One route is by reductive amination of ketone (10) available by Friedel-Crafts reaction from acid (11) which we can make by an FGA strategy (Chapter T 24). 

A combination of Friedel-Crafts alkylation and reduction can be achieved using InCl3 and chlorodimethylsilane. The Lewis acid presumably promotes both the Friedel-Craft reaction and the subsequent reduction.179... 

Intramolecular Friedel-Crafts reactions can sometimes compete with organosil-icon hydride reductions of benzylic-type alcohols to cause formation of undesired products. An example is the attempted reduction of alcohol 26 to the corresponding hydrocarbon. When 26 is treated with triethylsilane in trifluoroacetic acid at room temperature for 15 hours, a mixture of the two fluorene isomers 27 and 28 is obtained in a combined yield of 45%. None of the hydrocarbon structurally related to the substrate alcohol 26 is obtained.171 Whether this problem could be circumvented by running the reduction at a lower temperature or with a different acid remains subject to experimentation. 

Fluoride ions, aldehyde to alcohol reduction, 59-63 Friedel-Crafts reactions ... 

By a sequence of reactions, the two cyclopentadienyl rings can be connected. Using C2H5OCOCH2COCl as the starting acid chloride, it is possible to attach the acyl end to one of the C5H5 rings. Hydrolysis to remove the ethyl group and conversion of that end to an acid chloride followed by another Friedel-Crafts reaction and reduction of the product leads to... 

All three chlorine atoms of chloroform take part in the Friedel-Crafts reaction the product of the reaction with benzene is the important hydrocarbon triphenylmethane, the parent substance of the well-known class of dyes. Paraleucaniline, [(p) NH2.C6H4]3CH, has been converted into triphenylmethane by reductive hydrolysis of its tris-diazo-com-pound (E. and 0. Fischer). 

A carboxylic acid group may be introduced into the 2-position of dibenzofuran by Friedel-Crafts reaction with 2,2-dichloro-l,3-benzodioxole (catechol dichloromethylene ether) and hydrolysis of the resultant ester. Similarly, reaction with methylphenylcarbamoyl chloride produces the 2-(N-methyl-yV-phenylcarboxamide) or the 2,8-disubstituted derivative under more stringent conditions. Controlled reduction of these amides with lithium aluminum hydride supplies the corresponding aldehydes. ... 

The phenol 44 can obviously be made by a Friedel-Crafts reaction and the amine 45 by reduction of the nitro group in 46 as well as of the benzene ring. Since OH and OEt are both o, p-directing, the syntheses are simple.9... 

So the decision was taken to use succinic anhydride as the electrophile (chapter 5). Pyrroles prefer to react next to nitrogen with electrophiles (chapter 39), but with a large group on nitrogen 108 (j-P Si), Friedel-Crafts reaction occurred at the other position to give the keto-acid 109. Reduction to the benzylic alcohol and catalytic hydrogenation gave 110 in excellent yield. 

Sertraline (16) is an antidepressant that inhibits the uptake of serotonin in the central nervous system.148 It is marketed by Pfizer under the name Zoloft.149 One methodology that can be used relies on an asymmetric reduction (see also Chapter 16) (Scheme 31.11).150-156 The lactone can be used as a chiral starting material for the Friedel-Crafts reaction. The established stereogenic center in the tetralone controls the reduction of the imine.157 The alternative is a resolution approach (Scheme 31.12).148-153-158-161... 

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