Method for Producing 2-Formylfuran-4-Boronic Acid by the Metalation of 4-Halofurfural Acetals in the Presence of Suitable Boronic Acid Esters or Anhydrides

摘要

Methods for producing furfural-4-boronic acid by the reaction of furfural acetals (I), which are substituted by halogen in position 4, with boronic acid esters or anhydrides, by the subsequent metalation of compound (I) and the simultaneous or subsequent reaction with a boronic acid ester or anhydride to form an acetal-protected furfural-4-boronic acid ester. This product is subjected to acid hydrolysis to form furfural-4-boronic acid. In the formulae: X represents chlorine, bromine or iodine; R represents a branched, unbranched and/or cyclic, optionally substituted C₁-C₂₀ alkyl group, an optionally substituted C₆-C₁₂ aryl group or an optionally substituted C₃-C₈ cycloalkyl group, the two groups R together can form a ring; R', R'', R''' independently of one another represent acylic or cyclic, branched or unbranched, optionally substituted C₁-C₂₀ alkyl groups, or optionally substituted aryl groups, optionally two of the groups R', R'' and R''' together form a ring, or represent additional groups B(OR)₃.