Reaktion #44296

Reaktionsgleichung

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

Ausbeute 80.1%

Lösungsmittel

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGto stir for 1 hour at ambient temperature under nitrogen
2. 2
   SonstigeThe reaction was quenched with sat. aqueous solution of NH4Cl (10 mL)
3. 3
   workup.ADDITIONwere added
4. 4
   SonstigeThe organic layer was separated
5. 5
   Extraktionthe aqueous layer was extracted with EtOAc (3×50 mL)
6. 6
   Trocknendried over Na2SO4
7. 7
   Einengenconcentrated
8. 8
   Sonstigeto give the crude product as yellow oil
9. 9
   SonstigeThe oil was purified a silica gel column
10. 10
    Wascheneluting with EtOAc and hexanes

Vorschrift

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).

Quelle