tert-Butyl hydroperoxide → 1H-Indene-2-carboxylic acid, 5-chloro-2,3-dihydro-2-hydroxy-1-oxo-, methyl ester

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A chiral zirconium complex was prepared by stirring zirconium(IV) isopropoxide (0.560 g, 1.44 mmol) with 2,2′-[(1S,2S)-1,2-cyclohexanediylbis(iminomethylene)]bis[4,6-bis(1,1-dimethylethyl)phenol] (Formula IIIa wherein R6 is C(CH3)3, 1.00 g, 1.82 mmol) for 30 minutes in toluene (25 mL) at ambient temperature. The homogeneous solution was evaporated to dryness in vacuo, and the residue redissolved in toluene (8.70 g, 10 mL). A toluene solution of methyl 5-chloro-2,3-dihydro-1-oxo-1H-indene-2-carboxylate (1.53 g of a 21.55% by weight toluene solution, 1.47 mmol of methyl 5-chloro-2,3-dihydro-1-oxo-1H-indene-2-carboxylate) was added to the toluene solution of the chiral zirconium complex and the reaction mixture was heated to 55° C. Over the next 47 minutes, a toluene solution of methyl 5-chloro-2,3-dihydro-1-oxo-1H-indene-2-carboxylate (36.71 g of a 21.55% by weight toluene solution, 35.2 mmol of methyl 5-chloro-2,3-dihydro-1-oxo-1H-indene-2-carboxylate) and, simultaneously, an aqueous solution of tert-butyl hydroperoxide (70%, 4.69 g, 36.4 mmol) were co-fed to the reaction mixture at 55° C. After the two solutions were added, the reaction mixture was heated at 55° C. for an additional 6 hours, cooled to 25° C., and then filtered. After drying, 4.64 g (52.5%) of the S-enantiomer of methyl 5-chloro-2,3-dihydro-2-hydroxy-1-oxo-1H-indene-2-carboxylate was obtained as a white solid in 98% enantiomeric excess. Quantitative HPLC analysis of the filtrate and solids showed that the overall reaction proceeded with 85% conversion of methyl 5-chloro-2,3-dihydro-1-oxo-1H-indene-2-carboxylate, forming methyl 5-chloro-2,3-dihydro-2-hydroxy-1-oxo-1H-indene-2-carboxylate in 74% yield (87% chemoselectivity) and 75% enantiomeric excess of the S-enantiomer.

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