反応 #157671

反応方程式

CH2I2

ZnEt2

DME

alkene

(S,E)-Benzyl 8-(tert-butyldiphenylsilyloxy)-2-methyloct-5-en-4-ylcarbamate

→

title compound

Benzyl (1S)-1-(2-(2-(tert-butyldiphenylsilyloxy)ethyl)cyclopropyl)-3-methylbutylcarbamate

溶媒

DCM

DCM

反応条件

後処理

1. 1
   温度cooled to −20° C.
2. 2
   workup.STIRRINGAfter stirring for 10 min
3. 3
   温度to warm to rt
4. 4
   workup.STIRRINGwhile stirring
5. 5
   workup.WAITAfter 10 h
6. 6
   その他the reaction mixture was quenched with sat. aq. NH4Cl
7. 7
   workup.ADDITIONdiluted with DCM and water
8. 8
   その他the aqueous phase was separated
9. 9
   抽出extracted with EtOAc
10. 10
    乾燥The combined organic layers were dried (Na2SO4)
11. 11
    ろ過filtered
12. 12
    濃縮concentrated in vacuo

実験手順

To a solution of ZnEt2 (110 mg, 0.844 mmol) in dry DCM (2 mL) was added DME (distilled, 0.088 mL, 844 mmol). The reaction mixture was stirred at rt for 10 min under N2, then cooled to −20° C. and CH2I2 (0.137 mL, 1.687 mmol) was added dropwise over 4 min. After stirring for 10 min, a solution of the alkene 8b (149 mg, 0.281 mmol) in dry DCM (1 mL) was added dropwise over 5 min. The reaction mixture was allowed to warm to rt while stirring. After 10 h, the reaction mixture was quenched with sat. aq. NH4Cl and diluted with DCM and water, the aqueous phase was separated and extracted with EtOAc. The combined organic layers were dried (Na2SO4), filtered and concentrated in vacuo. Flash chromatography (SiO2, 9:1, hexanes/Et2O) afforded 785 mg (68%) of the title compound as a colorless oil. 1H NMR analysis showed only 1 diastereomer (>95:5 dr). [α]D23−26.8 (c 1.0, DCM); 1H NMR (300 MHz, CDCl3) δ 7.73-7.66 (m, 4H), 7.48-7.28 (m, 11H), 5.13-4.96 (m, 2H), 4.62 (appbd, 1H, J=8.4 Hz), 3.72 (appbt, 2H, J=6.4 Hz), 3.21 (m, 1H), 1.80-1.63 (m, 1H), 1.60-1.25 (m, 4H), 1.08 (s, 9H), 0.92 (appd, 6H, J=6.3 Hz), 0.79 (m, 1H), 0.51 (m, 1H), 0.40 (m, 1H), 0.30 (m, 1H); HRMS (ESI) m/z calcd for C34H45NO3SiNa 566.3066; found 566.3103.

出典