1: benzotriazol-1-ol; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride; N-ethyl-N,N-diisopropylamine / N,N-dimethyl-formamide / 0 - 20 °C / Inert atmosphere 2: lithium hydroxide hydrate / tetrahydrofuran; water / 3 h / 0 °C 3: N-ethyl-N,N-diisopropylamine; HATU / N,N-dimethyl-formamide / 0 - 20 °C / Inert atmosphere View Scheme

1: lithium hydroxide hydrate / tetrahydrofuran; water / 3 h / 0 °C 2: N-ethyl-N,N-diisopropylamine; HATU / N,N-dimethyl-formamide / 0 - 20 °C / Inert atmosphere View Scheme

1.1: 1-propanephosphonic acid cyclic anhydride; 4-methyl-morpholine / dichloromethane; acetonitrile / 5 h / -15 - 25 °C 2.1: triethylamine; water; lithium bromide / acetonitrile / 5.17 h / 0 - 20 °C 2.2: 0 - 2 °C / pH 3 - 4 3.1: 1-propanephosphonic acid cyclic anhydride; 4-methyl-morpholine / dichloromethane; acetonitrile / 1.5 h / -15 - 25 °C View Scheme

N-ethyl-N,N-diisopropylamine in dichloromethane

hydrogenchloride; 2-methylpropylboronic acid in methanol; n-heptane; water T=25 - 30°C; 1 - 2 h; Product distribution / selectivity;