반응 #52579

반응 방정식

pinacol

1-Octyne

di(1-isopropyl-3-methylbut-2-enyl)borane

formaldehyde

→

product

수율 67.0%

4,4,5,5-Tetramethyl-2-[(E)-1-octenyl]-1,3,2-dioxaborolane

수율 67.0%

용매

H2O

반응 조건

후처리

1. 1
   기타being below 5° C
2. 2
   기타The mixture formed
3. 3
   기타slowly quenched with H2O (3 ml) (with some gas evolution
4. 4
   workup.STIRRINGstirred at RT for 0.5 hour
5. 5
   기타at once (exothermic reaction, cooling bath necessary)
6. 6
   workup.STIRRINGThe reaction mixture was stirred at RT for 1 hour
7. 7
   workup.STIRRINGAfter stirring at RT for 24 hours
8. 8
   추출extracted with heptane (40 ml)
9. 9
   추출after which the organic extract
10. 10
    세척was washed with H2O (5×25 ml)
11. 11
    건조dried (Na2SO4)
12. 12
    기타evaporated under reduced pressure
13. 13
    기타The residue obtained
14. 14
    workup.DISTILLATIONwas carefully distilled under reduced pressure (bulb tube)

실험 절차

1-Octyne (2.95 ml, 20 mmol) was added slowly (˜20 min) to a suspension of freshly prepared di(1-isopropyl-3-methylbut-2-enyl)borane, with the reaction temperature being below 5° C. The mixture formed was stirred at 0° C. for 1 hour, slowly quenched with H2O (3 ml) (with some gas evolution occurring) and stirred at RT for 0.5 hour, after which a solution of formaldehyde (1.50 ml, 20 mmol, 37% strength by weight solution in water) was added all at once (exothermic reaction, cooling bath necessary). The reaction mixture was stirred at RT for 1 hour and then admixed with pinacol (2.60 g, 22 mmol). After stirring at RT for 24 hours, the mixture was diluted with H2O (40 ml) and extracted with heptane (40 ml), after which the organic extract was washed with H2O (5×25 ml), dried (Na2SO4) and evaporated under reduced pressure. The residue obtained was carefully distilled under reduced pressure (bulb tube), giving 3.19 g of the product (13.39 mmol, 67% yield) in the form of a colorless liquid, b.p. 70-80° C. (0.15 mm of Hg); IR (film) 2928, 1639, 1363, 1319, 1146 cm−1; 1H-NMR (300 MHz, acetone-d6) 6.55 (dt, 1H, J=18.0, 6.6 Hz), 5.35 (dt, 1H, J=18.0, 1.5 Hz), 2.17-2.09 (m, 2H), 1.50-1.20 (m, 8H), 1.21 (s, 12H), 0.90-0.85 (m, 3H); 13C-NMR (75.4 MHz, acetone-d6) 155.0, 83.6, 36.5, 32.5, 29.7, 29.2, 25.2, 23.3, 14.4;

출처