تفاعل #44296

معادلة التفاعل

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

المردود 80.1%

المذيبات

THF

ظروف التفاعل

المعالجة

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

الإجراء التجريبي

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).

المصدر