Lead, aryllead reagents

The reactivity of ketones towards aryllead (IV) triacetates is quite different from their reactivity towards lead (IV) tetraacetate, with which they are easily functionalised to give the a-acetoxyketones (see section 7.1.1.2). Under the usual conditions for arylation, ketones remain generally unaffected. Only ketone enolates and some specially activated ketones have been successfully arylated with aryllead reagents. 

The last system which has been briefly reported is the reaction of aryllead triacetates with copper (I) derivatives, such as copper (I) chloride, bromide and cyanide, which afford the corresponding aryl chlorides, bromides or cyanides. As the yields are only moderate, these reactions do not present any synthetic interest and they are only of mechanistic interest. A catalytic effect of copper was claimed to be operative in the reductive displacement of lead (II) by Cl , Br or CN , and this catalytic effect of copper compounds is also involved in the reactions of amine derivatives with aryllead reagents (see section 7.6.1). 

Aryllead triacetates, ArPb(OCOCH3)3. These reagents can be obtained by reaction of an aryl compound with lead tetraacetate in dichloroacetic acid or trichloroacetic acid (the reaction is slow in acetic acid).1 Another general route is reaction of a iliaiyltnercury with lead tetraacetate.2,3... 

O-Arylation of alcohols or phenols cannot be performed by copper diacetate-catalyzed reactions using aryllead triacetates as the source of the aryl ligand. However, Dodonov et at. reported that tetraphenyllead reacts with primary and secondary alcohols in the presence of copper diacetate to afford the derived O-phenyl ethers in moderate yields ranging from 1.25 to 1.8 mol. of ether per mole of the lead reagent (Equation (100)). Phenol and tert-butyl alcohol afforded lower yields of the ethers (0.72-0.95 mole per mole of the lead reagent).117... 

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