Process for preparing boronic and borinic acids

A process for preparing boronic acids of the formula (I) and borinic acids of the formula (II),

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• where
• the substituents R1′ to R5′ are each, independently of one another, H, CH3, straight-chain or branched C1-C8-alkyl, F, CnH2n+1−fFf where n=1 to 8 carbon atoms and f=1 to 2n+1 fluorine atoms, CH(OC1-C5-alkyl)2, C(C1-C5-alkyl), (OC1-C5-alkyl), CH2(OC1-C5-alkyl), CH(CH3)(OC1-C5-alkyl), C1-C5-alkoxy, N(C1-C5-alkyl)2, phenyl, substituted phenyl, aryl, heteroaryl, S(C1-C5-alkyl), Pphenyl2, Paryl2 or P(C1-C5-alkyl)2 and
• the symbols X, Y and Z are each, independently of one another, carbon or XR3′, YR2′ and/or ZR1′ are/is nitrogen or XR3′ and YR 2′ are together oxygen or XR3′ and YR2′ are together N(C1-C5-alkyl) or N(SiMe3) or XR3′ and YR2′ are together sulfur,
• by reaction of chloroaromatics of the formula (III) with lithium metal and boron compounds BW′W″W′″, where W′, W″ and W′″ are each, independently of one another, C1-C6-alkoxy, fluorine, chlorine, bromine, iodine, N(C1-C6-alkyl)2 or S(C1-C5-alkyl), in a solvent at temperatures in the range from −100 to 80° C.
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