Binol → HCID 19922588, compound

Temperature

0 °C

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).

1. customto react at 0° C. for 2 hours
2. filtrationThe solution was filtered through a pad of Celite
3. extractionthe filtrate was extracted three times with a 5 ml portion of diethyl ether
4. washThe combined organic layer was washed with a saturated sodium chloride aqueous solution
5. dry with materialdried over magnesium sulfate
6. customevaporated under reduced pressure
7. customto remove the solvent
8. customThe residue was purified by silica gel column chromatography (eluent: hexane/ethyl acetate=15/1 by volume)

ORD record

ord-9883f1029bbd4446a2e2ae9730ee84b4

Source dataset

uspto-grants-1995_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05434289