Reaktion #56742

Reaktionsgleichung

toluene-4-sulfonic acid (2R)-8-allyl-7-nitro-2,3-dihydro-benzo(1,4)dioxin-2-ylmethyl ester

ozone

oxygen

diisopropylethylamine

→

title compound

[7-Nitro-8-(2-oxoethyl)-2,3-dihydro-1,4-benzodioxin-2-yl]methyl 4-methylbenzenesulfonate

Lösungsmittel

methylene chloride

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONadded
2. 2
   Sonstigeto come to room temperature
3. 3
   WaschenIt was then washed with 300 mL portions of 2 N HCl (aq), water and saturated brine
4. 4
   Trocknendried over magnesium sulfate
5. 5
   Filtrationfiltered
6. 6
   Einengenconcentrated in vacuum

Vorschrift

A solution of 4.2 g (10 mmole) of toluene-4-sulfonic acid (2R)-8-allyl-7-nitro-2,3-dihydro-benzo(1,4)dioxin-2-ylmethyl ester in 400 mL of methylene chloride was cooled in a dry ice/isopropanol bath and saturated with ozone. It was then purged with oxygen and 2.6 g (20 mmole) of diisopropylethylamine added. The mixture was allowed to come to room temperature and stirred under nitrogen for 24 hours. It was then washed with 300 mL portions of 2 N HCl (aq), water and saturated brine, dried over magnesium sulfate, filtered and concentrated in vacuum to give 3.8 g of the (R)-enantiomer of the title compound as a white solid one-quarter hydrate, m.p. 116-120° C.

Quelle