Reactivity Insights of Methoxyphenyl Boronic Acids in Rieche Formylation Reaction.

In this study, mono- or poly-methoxylated phenyl boronic acids, were subjected to Rieche formylation. Unexpectedly the corresponding ipso-substituted aryl aldehydes were obtained in excellent yields and, for some of these substrates, the formylated arylboronic acids were also synthesized in moderate yields. These findings provide new insights into the general reactivity and versatility of arylboronic acids.