SYNTHESIS AND REACTIONS OF SOME SUBSTITUTED 1-PHENYLETHANEBORONIC ESTERS

1-Phenylethaneboronic esters bearing p-methyl, p-chloro substituents been synthesized by hydrogenation of the α-styreneboronic esters. An alternative synthesis involving rearrangement of aryl(α-haloethyl)borinic esters was also explored with partially successful results. Other substituted 1-phenylethaneboronic esters prepared from dibutyl α-styreneboronate included the α-bromo, α-butoxy, and α-dibutoxyboryl derivatives. Displacement of boron by mercuric chloride has been surveyed. The p-chlorophenylethaneboronic ester reacts with mercuric chloride about 0.1 or 0.2 times as fast as the unsubstituted compound to yield the corresponding 1-phenylethylmercuric chloride. The α-substitued boronic esters yield unstable mercury derivatives which decompose to mercurous chloride and acetophenone. © 1969.