反应详情

6,8-Dimethyl-2-oxa-spiro[4.5]dec-7-ene-1,3-dione (prepared as above in EXAMPLE I, 140 g) was fed slowly into an ethyl magnesium chloride (C2H5MgCl) solution in tetrahydrofuran (THF) (2 M, 1.53 L) while the temperature was kept under 25° C. After the feeding was completed, the reaction was aged at room temperature for about an hour. The reaction mixture was then poured into hydrochloric acid (HCl) (2 M) containing ice. Toluene was added. The organic and aqueous layers were shaken in a separatory funnel and separated. The aqueous layer was further washed with toluene. The organic layers were combined and washed with sodium carbonate (Na2CO3) solution until basic. The resulting solution was distilled to afford 3,3-diethyl-6,8-dimethyl-2-oxa-spiro[4.5]dec-7-en-1-one (170 g).

1. customwas kept under 25° C
2. waitthe reaction was aged at room temperature for about an hour
3. additioncontaining ice
4. customseparated
5. washThe aqueous layer was further washed with toluene
6. washwashed with sodium carbonate (Na2CO3) solution until basic
7. distillationThe resulting solution was distilled