Binol → HCID 19922588, compound

Participants

Reaction Conditions

Reaction Steps

An (S)-binaphthol-dichlorotitanium complex solution was prepared in the same manner as the preparation of the (R)-binaphthol-dichlorotitanium complex solution in Example 1 except that (S)-binaphthol was used in place of (R)-binaphthol. 0.5 ml (0.1 mmol) of the (S)-binaphtholdichlorotitanium complex solution were cooled to 0° C., and 218 mg (1 mmol) of (E)-1-t-butylthio-1-trimethylsilyloxy-1-propene (93% E) and subsequently 88 mg (1 mmol) of freshly distilled methyl glyoxylate and 0.5 ml of toluene were added thereto, followed by allowing the mixture to react at 0° C. for 2 hours. The resulting mixture was poured into 10% hydrochloric acid-methanol cooled at 0° C. The solution was filtered through a pad of Celite, and the filtrate was extracted three times with a 5 ml portion of diethyl ether. The combined organic layer was washed with a saturated sodium chloride aqueous solution, dried over magnesium sulfate, and evaporated under reduced pressure to remove the solvent. The residue was purified by silica gel column chromatography (eluent: hexane/ethyl acetate=15/1 by volume) to obtain mg of methyl 4-t-butylthio-2-hydroxy-3-methyl-4-oxobutyrate in a yield of 80% (16% syn, 84% ee; 84% anti, 93% ee).

Provenance & Evidence