Oka N,
Yamada T,
Sajiki H,
Akai S,
*,
Ikawa T.
*
Osaka University and Gifu Pharmaceutical University, Japan
Aryl Boronic Esters Are Stable on Silica Gel and Reactive under Suzuki–Miyaura Coupling Conditions.
Org. Lett. 2022;
24: 3510-3514
Key words
aryl boronic esters - Suzuki–Miyaura cross-coupling - 1,1,2,2-tetraethylene glycol (Epin)
Significance
The synthesis and application of arylboronic 1,1,2,2-tetraethylethylene glycol esters, Ar–B(Epin), is disclosed. These aryl boronates are readily accessible via dehydrative esterification of boronic acids, metalation of aryl bromides or Miyaura borylation. Substitution of the methyl units of the pinacol esters Ar–Bpin by ethyl groups leads to higher stability, and the corresponding arylboronic esters Ar–B(Epin) are easily purified by column chromatography on silica gel.
Comment
The novel arylboronic esters show enhanced reactivity in Suzuki–Miyaura cross-couplings, providing the coupling products in excellent yields. These organoboron compounds represent a viable alternative to the commonly used aryl boronic acids or pinacol esters.
