Alkyl addition, aromatic ring, effect

Bromination of Aromatic Rings 593 Other Aromatic Substitutions 597 Alkylation of Aromatic Rings The Friedel-Crafts Reaction Acylation of Aromatic Rings 604 Substituent Effects in Substituted Aromatic Rings 605 An Explanation of Substituent Effects 610 Trisubstituted Benzenes Additivity of Effects... 

In a study aimed at the identification of products of free radical reactions with polystyrene- and aromatic-based PEMs using model compounds, Hiibner and Roduner observed the addition of free radicals to the aromatic rings, preferentially in the ortho position to alkyl- and RO-substituents (in polystyrene- and aromatic-based PEMs, the para position is blocked by the presence of the sulfonic acid group). This study demonstrated the combined ortho-activation by these substituents and the meta-directing effect... 

PaMeSt chain end] >10) before the addition of IB. This is based on a recent finding that the living cationic polymerization of pClaMeSt can be accomplished under conditions identical to those used for the synthesis of poly (aMeSt-fc-IB) copolymer [22, 23]. Importantly, the living PpClaMeSt chain end is very stable and there is no loss of livingness even after 5 h under monomer starved conditions. This is attributed to the reduced tendency of intramolecular alkylation due to the particularly large deactivating effect of the p-chloro substituent on the 2,5-positions of the aromatic ring. 

In (C5Me5)Rh(C2H3SiMe3)2-catalyzed C-H/olefin coupling the effect of the coordination of the ketone carbonyl is different from that in the ruthenium-catalyzed reaction [10], In the rhodium-catalyzed reaction all C-H bonds on the aromatic ring are cleaved by the rhodium complex without coordination of the ketone carbonyl. Thus, C-H bond cleavage and addition of Rh-H to olefins proceed without coordination of the ketone carbonyl. After addition of the Rh-H species to the olefin, a coordinatively unsaturated Rh(aryl) (alkyl) species should be formed. Coordination of the ketone carbonyl group to the vacant site on the rhodium atom leads... 

Chatani and coworkers reported the effective carbonylation of the C-H bond in the aromatic ring via Ru3(CO)12-catalyzed reaction of olefins and CO with heteroaromatics (Eq. 101) [159] and substituted benzene (Eq. 102) [160]. For more examples of the acylation of five-membered heteroaromatic compound see Ref. [ 161 ]. The reaction is closely related to the process of the ortho alkylation of substituted aromatic compounds and involves an additional step of CO insertion. 

Extensive work by Yamaki and Tobishima was devoted to the effect of additives on Li cycling efficiency in ethers and alkyl carbonates [265], This included the use of cation complexing compounds (e.g., 12 crown 4, TMEDA), reactive organic compounds (e.g., quinoneimine derivatives), and adsorption compounds (e.g., large tetraalkyl ammonium chloride substituted with aromatic rings) [265],... 

The effects of substituents on the basic nature of imidazole are summarized in Section 4.02.1.3.4. Tables 1 and 2 list the basic pKa values of some representative imidazoles and benzimidazoles. From these it can be seen that methyl and other alkyl substituents exert a weak, base-strengthening inductive effect which is additive. Aromatic substituents decrease basic strength, while groups attached to these aryl rings exert their normal behavior. In fact, Hammett studies have permitted prediction with reasonable accuracy and correlation of p/Ca values for a variety of imidazoles. In a study of meta- and para-substituted 1-phenylimidazoles Pozharskii <70CHE194) has shown not only that 1-phenylimidazole is a... 

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