Bromobenzene acylation

Partial rate factors may be used to estimate product distributions in disubstituted benzene derivatives The reactivity of a particular position in o bromotoluene for example is given by the product of the partial rate factors for the corresponding position in toluene and bromobenzene On the basis of the partial rate factor data given here for Fnedel-Crafts acylation predict the major product of the reaction of o bromotoluene with acetyl chlonde and aluminum chloride... 

Smeets and Verhulst413 obtained cleanly second-order kinetics, equation (194) where n = 1 in the acylation of aromatics using bromobenzene as solvent... 

Bio-oxidation of bromobenzene 11 catalyzed by Pseudomonas putidae leads to diol 12. Protection of diol 12, followed by the addition of an acyl nitroso dienophile and subsequent reduction gives compound 14. This compound can be used as the key intermediate in the preparation of (+)-l-deoxy-galacto-nojirimycin (16) and related indolizidine compounds (15) (Scheme 8-5).12... 

Carbonylation of bromobenzene (Scheme 5.7) with [Pd(TPPTS)3] required still higher temperatures (150 T). The possible acyl intermediates of such reactions [PdBr(C6H5CO) Ph3)2] and [PdBr(C6H5CO)(TPPTS)2] were synthetized and characterized [26]. Bromobenzene was also carbonylated to benzoic acid in water/toluene using a catalyst prepared from [PdCl2(COD)j and 27 in the presence of NEt3 [21]. 

A reaction of bromobenzene with ethyl malonate in the presence of sodamide affords homophthalimide [103], This fascinating reaction involves sequential elimination, addition, intramolecular acylation, fragmentation, and addition. Excellent polarity alternation along the chains of atoms in various intermediates allows so many steps to proceed efficiently. 

The one-step double functionalization of aromatics—that is, alkylation and acylation—can be accomplished with alkanes or cycloalkanes (in large excess) using the aprotic organic superacids RCO+Al2X7 (R = alkyl, aryl, X = Cl, Br)391 [Eq. (5.152)]. However, the method can be used only for benzene and bromobenzene. 

A side-chain acyl chloride cyclizes on to a neighbouring thiol group (formed in situ by demethylation of a methylthio ether) under mild conditions. The corresponding thiopyran-4-one is obtained by the reaction of a 2-mercaptobenzoate ester and bromobenzene with lithium -isopropylcyclohexylamide (LICA) at low temperature. 

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