Br[C:2]1[C:6]2[CH:7]=[CH:8][CH:9]=[CH:10][C:5]=2[O:4][C:3]=1[CH2:11][CH3:12].C([Li:17])CCC>>[Li:17][C:2]1[C:6]2[CH:7]=[CH:8][CH:9]=[CH:10][C:5]=2[O:4][C:3]=1[CH2:11][CH3:12]comprising contacting 3-bromo-2-ethylbenzofuran with n-butyllithium at a temperature less than −75° C. to form 3-lithio-2-ethylbenzofuran, contacting the 3-lithio-2-ethylbenzofuran at a temperature less than −75° C. with an isopropyl boronate cyclic ester corresponding to the formula:
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