反応 #44296

反応方程式

2-methoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

4-iodo-1-[2-(tetrahydro-pyran-2-yloxy)-ethyl]-1H-pyrazole

iPrMgCl

→

1-[2-(tetrahydro-pyran-2-yloxy)-ethyl]-4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-1H-pyrazole

収率 80.1%

溶媒

THF

反応条件

後処理

1. 1
   workup.STIRRINGto stir for 1 hour at ambient temperature under nitrogen
2. 2
   その他The reaction was quenched with sat. aqueous solution of NH4Cl (10 mL)
3. 3
   workup.ADDITIONwere added
4. 4
   その他The organic layer was separated
5. 5
   抽出the aqueous layer was extracted with EtOAc (3×50 mL)
6. 6
   乾燥dried over Na2SO4
7. 7
   濃縮concentrated
8. 8
   その他to give the crude product as yellow oil
9. 9
   その他The oil was purified a silica gel column
10. 10
    洗浄eluting with EtOAc and hexanes

実験手順

To a solution of 4-iodo-1-[2-(tetrahydro-pyran-2-yloxy)-ethyl]-1H-pyrazole (1.0 g, 3.1 mmol) in anhydrous THF (8 mL) was added iPrMgCl (2M in THF, 3.10 mL, 6.21 mmol) at 0° C. drop by drop under nitrogen. The reaction was stirred for 1 hour at 0° C. under nitrogen. To the solution was added 2-methoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (0.736 g, 4.66 mmoL) at 0° C. and the resulting yellow solution was allowed to stir for 1 hour at ambient temperature under nitrogen. The reaction was quenched with sat. aqueous solution of NH4Cl (10 mL). EtOAc (50 mL) and sat aqueous NH4Cl solution (10 mL) were added. The organic layer was separated, and the aqueous layer was extracted with EtOAc (3×50 mL), dried over Na2SO4, and concentrated to give the crude product as yellow oil. The oil was purified a silica gel column eluting with EtOAc and hexanes to provide 1-[2-(tetrahydro-pyran-2-yloxy)-ethyl]-4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-1H-pyrazole as clear oil (800 mgs, 80% yield). 1H NMR (300 MHz, DMSO-d6) δ 7.91 (s, 1H) 4.48-4.54 (m, 1H) 4.26-4.33 (m, 2H) 3.86-3.90 (m, 1H) 3.66-3.76 (m, 1H) 3.45-3.57 (m, 1H) 3.33-3.39 (m, 1H) 1.33-1.70 (m, 6H) 1.24 (s, 12H).

出典