N,N,N',N'-Tetramethylethylenediamine → (+/-)-5-Bromo-1,3-dihydrospiro[indene-2,3'-indol]-2'(1'H)-one

Participants

Reaction Conditions

Reaction Steps

To a solution of oxindole (363 mg, 2.73 mmol) at −78° C. in THF (15 mL) was added butyllithium (2.5 M in hexanes, 2.29 mL, 5.73 mmol) dropwise, followed by the dropwise addition of tetramethylethylenediamine (0.905 mL, 6.00 mmol). The solution was stirred for 1 h at −78° C., then a solution of 4-bromo-1,2-bis(bromomethyl)benzene [Anderson et al., J. Org. Chem. 1979, 44(9), 1519-1533] (1.87 g, 5.45 mmol) in THF (5 mL) was added dropwise. The reaction solution was stirred at −10 to −20° C. for 2 h and at ambient temperature for 16 h. The reaction mixture was partitioned between saturated NH4CI (50 mL) and EtOAc (50 mL). The aqueous phase was further extracted with EtOAc (2×50 mL), and the combined organic layers were dried over Na2SO4, filtered, and concentrated under reduced pressure. The crude product was purified by silica gel chromatography, eluting with a gradient of hexane:EtOAc—100:0 to 50:50, to give the title compound. MS: m/z=315 (M+1).

Provenance & Evidence