Friedel-Crafts acrylation

Formaldehyde-to-phenol ratios, 404 V-Formyl amines, 158 Fourier transform infrared (FTIR) spectrometry, 116, 300, 387, 407-408 Fradet, Alain, 17 Free-radical copolymerization, 59 Friedel-Crafts acrylation polymerization, 332-334... 

Weak Base Anion Exchangers. Both styrenic and acrylic copolymers can be converted to weak base anion-exchange resins, but different synthetic routes are necessary. Styrene—DVB copolymers are chloromethylated and aminated in a two-step process. Chloromethyl groups are attached to the aromatic rings (5) by reaction of chloromethyl methyl ether [107-30-2], CH3OCH2Cl, with the copolymer in the presence of a Friedel-Crafts catalyst such as aluminum chloride [7446-70-0], A1C13, iron(III) chloride [7705-08-0]9 FeCl3, or zinc chloride [7646-85-7], ZnC. ... 

The polar monomers cited include acrylic acid, acrylic esters, meth-acrylic acid, methacrylic esters, acrylonitrile, methacrylonitrile, acrolein, and vinyl acetate. While this list is reasonable, it also includes vinyl halides and vinylidene halides, although no examples with the latter are given. In view of the fact that the vinyl and vinylidene halides do not form complexes with Friedel-Crafts catalysts, these monomers would not be expected to be operable, as demonstrated by the results of Imoto (30). 

Angew. Chem. Int. Ed. Engl. 44, 3668-3688, 2005 Kent, M. and Tepe, J.J., One-pot Friedel-Crafts/ Robinson-Gabriel synthesis of oxazoles using oxazolone templates, J. Org. Chem. 70, 4211 213, 2005 Movassaghi, M. and Ondrus, A.E., Enantioselective total synthesis of tricyclic myrmicarin alkaloids, Org. Lett. 7, 4423 426, 2005 Paizs, C., Katona, A., and Retey, J., The interaction of heteroaryl-acrylates and alanines with phenylalanine ammonia-lyase form parsley. Chemistry 12, 2739-2744, 2006. Cuprous ions have been observed to promote a Friedel-Crafts acylation reaction (Kozikowski, A.P. and Ames, A., Copper(l) promoted acylation reactions. A transition metal-mediated version of the Friedel-Crafts reaction, J. Am. Chem. Soc. 102, 860-862, 1980). 

However, catalysis of Diels-Alder reactions is satisfactory only with specific dienophiles, for example, the two cited in the examples, acrolein, and acrylic acid. Another limitation is that some dienes polymerize in the presence of a Friedel-Crafts catalyst. 

Essentially every analog and derivative prepared in the project was ultimately derived from the corresponding 3-chloro-pyri-dazine. With the exception of a few 3-chloropyridazines which originated from a Friedel-Crafts acylation of benzene, the large majority of chloropyridazines were prepared by a sequence based on the addition of the masked acyl anion equivalent of a benzaldehyde to the appropriately substituted acrylate ester. 

A versatile non-Friedel-Crafts approach to naphthols is provided by condensation of the toluic acid sulfoxide with substituted acrylates or methyl vinyl ketone. Sequential conjugate addition and acylation of the first formed anion leads to the tetralone. Pyrolysis leads to aromatiza-tlon by loss of sulfinic acid. 

Michael addition of acrylic acid to the chloroamine 32 is straightforward and Friedel-Crafts cyclisation of 35 gives only 31, presumably because the position next to the chlorine atom is slightly disfavoured both sterically and electronically. Chlorination and oxidation are conveniently carried out in the same step and the two halves (26 and 28) of this convergent synthesis are combined to give amopyroquine 25. 

Starting from the readily available parent arenes, ketones 54a,b were prepared by standard Friedel-Crafts chemistry. Environment-friendly electrochemical carboxylation of these gave a-hydroxy acids 55a,b, from which acrylic acids 56a,b were easily obtained. Their reduction, catalyzed by the modified Noyori complex Ru(acac)2/BINAP, afforded in high yields the (. -enantiomers of acids 22 and 57 having 98% and 96% e.e., respectively. Improvements of both processes have been reported [64,65],... 

Friedel-Crafts alkylations. a-(l-Acetoxyalkyl)acrylic acid derivatives that are readily obtained via the Baylis-Hillman reaction are good alkylating agents. The... 

Inspired by the use of chiral imidazolidinones as highly enantioselective catalysts for Diels-Alder, 1,3-dipolar cycloaddition and Friedel-Crafts reactions, Tan et have synthesized a series of novel chiral imidazolines and examined their application in MBH reactions. Up to 54% ee and high yields were obtained by using stoichiometric amounts of imidazoline 175 for the MBH reactions of various aromatic aldehydes with unactivated acrylates. Furthermore, the imidazolines were also suitable promoters for reactions between aromatic aldehydes and alkyl vinyl ketone. Using 50 mol.% of imidazoline 176, which bears a chiral methylnaphthyl group, afforded adducts in high yield with up to 78% ee (Scheme 2.86). These chiral imidazolines are readily prepared from commercially available amino alcohols and can be easily recovered for reuse without loss of product enantioselectivity. 

Subsequently, MBH adducts were successfully utilized as novel stereodefined electrophiles in the Friedel-Crafts reaction with benzene in the presence of a Lewis acid " and sulfuric acid, leading to the stereoselective synthesis of (Z)- and ( )-functionalized trisubstituted alkenes. Notably, MBH adducts obtained from acrylonitrile provide high (Z)-stereoselectivities, while adducts derived from methyl acrylate and aromatic aldehydes give high ( )-stereo-selectivities. When the MBH adducts drived from methyl acrylate and aliphatic aldehydes were involved in the Friedel-Crafts reaction, no significant stereoselectivity was observed (Scheme 3.29). 

The MBH adducts, derived from methyl acrylate and aldehydes, have been employed successfully to the general synthesis of 3-arylidene(alkylidene)chro-man-4-ones 94, which involved an intramolecular Friedel-Crafts reaction as... 

By intramolecular Friedel-Crafts cyclization of 33 with 95% sulfuric acid in CCI4 at room temperature for 0.5-4 h, 2-(9/f-fluoren-9-yl)acrylic acid derivatives 34 have been obtained in 39-92% yields (Scheme 4.11). ... 

Sibi MP, Coulomb J, Stanley LM. Enantioselective enolate protonations Friedel-Crafts reactions with a-substituted acrylates. Angew. Chem. Int. Ed. 2008 47 9913-9915. 

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