反应详情

A solution of the neo-pentylmagnesium bromide prepared above (60 mL) was added dropwise at room temperature over 20 min to a solution of zinc chloride (60 mL, 0.5 M in tetrahydrofuran, 30.0 mmol). Following Grignard addition, the reaction mixture was stirred for 0.5 h to yield a white heterogenous suspension. [1,1′-Bis(diphenylphosphino)ferrocene]dichloropalladium(II) complex with dichloromethane (1:1) (816 mg, 1.0 mmol) was added in one portion followed by dropwise addition of a solution of the dioxolane prepared in step 1 (2.69 g, 10.0 mmol) in tetrahydrofuran (10 mL) to yield a yellow reaction mixture, which was then heated at reflux for 1 h to yield a brown solution. The reaction mixture was cooled to room temperature and carefully quenched with 10% hydrochloric acid (100 mL) and the reaction mixture was stirred at room temperature overnight. The reaction mixture was diluted with diethyl ether and the phases separated. The organic phase was then washed with water, saturated sodium chloride, dried (sodium sulfate), filtered, and concentrated under reduced pressure to yield a black oil. Purification by flash column chromatography (silica, 19:1 hexanes/ethyl acetate) afforded compound (4) (2.17 g, 99%) as a yellow oil: IR (ATR) 3359, 2957, 1762, 1686, 1521, 1236, 1126, 1076, 1053, 1028 cm−1; 1H NMR (300 MHz, CDCl3) δ 7.79 (s, 1H), 7.26–7.22 (m, 1H), 7.15 (m, 1H), 2.96–2.92 (m, 2H), 2.67–2.62 (m, 2H), 2.50 (s, 2H), 2.17–2.08 (m, 2H), 0.89 (s, 9H); ESI MS m/z 217 [C15H20O+H]+; HPLC: (Method D) >99% (AUC), tR=13.30 min.

1. additionFollowing Grignard addition
2. customto yield a white heterogenous suspension
3. customto yield a yellow reaction mixture, which
4. temperaturewas then heated
5. temperatureat reflux for 1 h
6. customto yield a brown solution
7. customcarefully quenched with 10% hydrochloric acid (100 mL)
8. stirringthe reaction mixture was stirred at room temperature overnight
9. additionThe reaction mixture was diluted with diethyl ether
10. customthe phases separated
11. washThe organic phase was then washed with water, saturated sodium chloride
12. dry with materialdried (sodium sulfate)
13. filtrationfiltered
14. concentrationconcentrated under reduced pressure
15. customto yield a black oil
16. customPurification by flash column chromatography (silica, 19:1 hexanes/ethyl acetate)