[CH3:1][O:2][CH2:3][CH:4]=[CH2:5].C12BC(CCC1)CCC2.C[O-].[Na+].Br[C:19]1[CH:20]=[C:21]([CH:27]=[CH:28][CH:29]=1)[C:22]([O:24][CH2:25][CH3:26])=[O:23]>C1COCC1>[CH3:1][O:2][CH2:3][CH2:4][CH2:5][C:19]1[CH:20]=[C:21]([CH:27]=[CH:28][CH:29]=1)[C:22]([O:24][CH2:25][CH3:26])=[O:23]To a THF solution (0.1 M) of allyl methyl ether (1.4 eq.) was added, at 0° C., 9-borabicyclo[3.3.1]nonane (2.4 eq.) over a period of 30 min. The solution was stirred at 0° C. for 1 h and then warmed slowly to RT over 16 h. To the resulting clear solution was then added sodium methoxide (2.4 eq.), Cl2Pd(dppf)-dichloromethane complex (5% loading) and ethyl 3-bromobenzoate (1 eq.). The now brown suspension was heated to reflux for 16 h. The reaction mixture was cooled to RT, quenched with sat. aq. NH4Cl and extracted with ether. The combined organic extracts were washed with brine, dried over MgSO4 and filtered. Concentration of the filtrate in vacuo afforded a brown oil. Purification of the crude product thus obtained by way of flash chromatography (SiO2, Hex→4:1 (v/v) Hex:EtOAc) afforded the title compound as a light yellow oil.
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