Formaldehyde → trans-4,4,5,5-Tetramethyl-2-oct-1-enyl-1,3,2-dioxaborolane

Temperatur

0 °C

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;

1. custombeing below 5° C
2. customThe mixture formed
3. customslowly quenched with H2O (3 ml) (with some gas evolution
4. stirringstirred at RT for 0.5 hour
5. customat once (exothermic reaction, cooling bath necessary)
6. stirringThe reaction mixture was stirred at RT for 1 hour
7. stirringAfter stirring at RT for 24 hours
8. extractionextracted with heptane (40 ml)
9. extractionafter which the organic extract
10. washwas washed with H2O (5×25 ml)
11. dry with materialdried (Na2SO4)
12. customevaporated under reduced pressure
13. customThe residue obtained
14. distillationwas carefully distilled under reduced pressure (bulb tube)

ORD-Eintrag

ord-5c4a0da9e0f84a4aa3c7be80616e3dac

Quelldatensatz

uspto-grants-2005_02

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US06855848B2