Oxygen → HCID 10890919, compound

Participants

Reaction Steps

8.00 g (29.9 mmol) of 1,4-diacetyl-1,4,5,6-tetrahydropyrazine-2-carboxylic acid tert-butylamide, 10.0 mg (18 μmol) of 1-[1(R)-(di-tert-butylphosphino)-ethyl]-2(S)-(diphenylphosphino)ferrocene and 6.0 mg (16 μmol) of bis(bicyclo[2.2.1]hepta-2,5-diene)rhodium(I) tetrafluoroborate were placed in an autoclave, oxygen being excluded. After flushing with argon, 80 ml of oxygen-free methanol was added. Hydrogenation was carried out at an initial pressure of 50 bar and a temperature of 110° C. for 20 hours. Working-up of the reaction mixture analogously to Example 19 gave 10.50 g (75%) of the title product. GC analysis showed a conversion of 97 percent. After cleavage of the protecting groups with hydrochloric acid, the enantioselectivity of the hydrogenation was determined by GC analysis, giving an ee of 90.7 percent. The melting point of the title compound was: 139.9° to 150.6° C. Other data concerning the title compound was:

Provenance & Evidence