1: 4-(dihydroxyboryl)benzoic acid With benzotriazol-1-ol; O-(1H-benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate; N-ethyl-N,N-diisopropylamine in N,N-dimethyl-formamide 2: (cyclopropylmethyl)amine in N,N-dimethyl-formamide Further stages.;