Tetrafluoroboric acid → Hedione

Beteiligte Stoffe

Reaktionsschritte

In a glovebox, into a 10 ml glass vial were placed 15.5 mg (0.0485 mmole) of [(COD)Ru(methylallyl)2], 14.9 mg (0.0485 mmole) of (R,R)-Me-DuPHOS and 250 μl of methyl 3-oxo-2-pentyl-1-cyclopentene-1-acetate (1.08 mmole). To this suspension was added 0.630 ml of a 0.081 M solution of titrated HBF4.etherate (0.049 mmole) in CH2Cl2 with stirring. This concentrated solution was stirred for 1.5 hours, after which 21.5 g (95.9 mmole) of methyl 3-oxo-2-pentyl-1-cyclopentene-1-acetate and 11.5 ml of CH2Cl2 were added. The resulting yellow solution was placed in a 75 ml autoclave, purged with hydrogen and pressurized to 90 bar of hydrogen. After 8 hours, the solution was exposed to air and passed through a column of silica gel to separate the catalyst. This gave a 99% yield of the desired Hedione® product with the following ratios of isomers: cis/trans=98/2; (+)-cis/(−)-cis=82.4/17.6, 64.8% ee.

Herkunft & Nachweise