Hydrochloric Acid → 3-Chloro-5-(dihydroxyboryl)-1-(4-isopropoxyphenyl)indole-2-carboxylic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

To solution of 3-chloro-5-iodo-1-(4-isopropoxyphenyl)-1H-indole-2-carboxylic acid ethyl ester (1.45 g, 3.0 mmol, see step (a) above) in THF (9 mL) was added i-PrMgCl×LiCl (0.95 M solution in THF; 3.26 mL, 3.1 mmol) at −40° C. over 5 min. After stirring for 15 min at −40° C., B(OEt)3 (1.56 mL, 9.0 mmol) was added. The temperature of the reaction mixture was allowed to reach 0° C. over 2 h, then HCl (2.5 M solution in water; 3.6 mL, 36 mmol) was added and stirring continued for a further 1 h at 0° C. The reaction mixture was diluted with brine (70 mL) and extracted with t-BuOMe (4×70 mL). The combined organic extracts were washed with brine (100 mL), dried over Na2SO4 and concentrated. The solid thereby obtained was washed several times with light petrol and filtered affording pure sub-title compound (1.04 g, 86%)

Provenance & Evidence