Aromatic compounds from aryl esters

The palladium-catalyzed carbonylation of aryl halides in the presence of various nucleophiles is a convenient method for synthesizing various aromatic carbonyl compounds (e.g., acids, esters, amides, thioesters, aldehydes, and ketones). Aromatic acids bearing different aromatic fragments and having various substituents on the benzene ring have been prepared from aryl iodides at room temperature under 1 atm... 

The synthesis of bistannylated aromatic compounds can be achieved in good yields via a simple two-step sequence from phenols [44]. This methodology enables, for example, the transformation of BINOL into the corresponding aryl diethylpho-sphate ester, which by reaction with Me3Sn ions in liquid ammonia under irradiation affords 2,2 -bis(trimethylstannyl)-l,l -binaphthyl in an overall yield of 66% (Scheme 10.27). 

The Fries rearrangement used for the preparation of aryl ketones from phenolic esters is now one of the most significant reactions in the synthetic chemistry of aromatic compounds, both in the classical version (equation 99) and in the newest modifications (see Section IV.D.3). 

Aryl-2,3-dichlorocyclopropenylium salts, prepared from trichlorocyclopropenylium tetra-chloroaluminate and an activated aromatic compound in situ, reacted with three equivalents of an appropriate alcohol. Careful hydrolysis of the product yielded 2-alkoxy-3-arylcycloprope-nones. °° Reaction of l-aryl-2,3,3-trichlorocyclopropene with alcohols gave arylpropynoate ortho esters. 

Carbonyls of aroyloxyl groups (R2 = Aryl, Table 2, entries 42-52 and 59-68) range from 1750 to 1767 cm-1 and are similarly increased relative to normal aromatic esters (1715-1730 cm-1). Most benzoyloxy compounds give carbonyls between 1760 and 1765 cm-1 but those that are para substituted with donor groups, as well as those with polycyclic aroyloxyl groups, have carbonyls in the lower range of 1750-1760 cm-1. 

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