Reaktion #658330

Reaktionsgleichung

(S,Z)-3-(2,2-dimethyl-1,3-dioxan-4-yl)prop-2-en-1-ol

t-butylbromoacetate

cesium hydroxide monohydrate

→

3

Ausbeute 97.0%

(S,Z)-t-butyl 2-(3-(2,2-dimethyl-1,3-dioxan-4-yl)allyloxy)acetate

Ausbeute 97.0%

Lösungsmittel

acetonitrile

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONTo a round bottom flask charged with activated molecular sieves (6.0 g)
2. 2
   FiltrationThe solid was filtered out
3. 3
   Einengenthe solvent was concentrated under vacuum
4. 4
   Sonstigethe residue was purified by flash column chromatography (5% ethyl acetate/hexanes)

Vorschrift

To a round bottom flask charged with activated molecular sieves (6.0 g) was added a solution of substrate, (S,Z)-3-(2,2-dimethyl-1,3-dioxan-4-yl)prop-2-en-1-ol (9.0 g, 52.0 mmol) in acetonitrile (150 mL), followed by t-butylbromoacetate (9.90 mL, 67.2 mmol), tetrabutylammonium iodide (2.0 g, 5.2 mmol) and cesium hydroxide monohydrate (13.1 g, 78.0 mmol) at room temperature. The reaction was allowed to stir for 6 h. The solid was filtered out and the solvent was concentrated under vacuum; the residue was purified by flash column chromatography (5% ethyl acetate/hexanes) to afford 3 (14.4 g, 97% yield) as a colorless oil. Rf=0.57 (30% ethyl acetate/hexanes). [α]23D=+ 22.9 (c 1.29, CHCl3) 1H NMR (300 MHz, Chloroform-d) δ 5.72-5.51 (m, 2H), 4.77-4.65 (m, 1H), 4.26-4.09 (m, 2H), 4.01 (dd, J=17.3, 2.6 Hz, 1H), 3.93 (d, J=3.6 Hz, 2H) 3.82 (ddd, J=11.8 Hz, 5.4 Hz, 1.4 Hz, 1H), 1.79-1.65 (m, 1H), 1.48 (s, 3H), 1.46 (s, 10H), 1.37 (s, 3H). 13C NMR (75 MHz, CDCl3) δ 169.5, 134.1, 127.7, 98.3, 81.5, 67.6, 66.8, 65.5, 59.5, 31.1, 29.9, 28.0, 19.1.

Quelle