Reaktion #53856

Reaktionsgleichung

triethylamine

trans-(4-Formyl-cyclohexyl)-methyl-carbamic acid tert-butyl ester

triphenylphosphine

tetrabromomethane

→

trans-[4-(2,2-Dibromo-vinyl)-cyclohexyl]-methyl-carbamic acid tert-butyl ester

Ausbeute 67.0%

Lösungsmittel

CH2Cl2

CH2Cl2

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturheated up
2. 2
   Temperaturheated up
3. 3
   Temperaturto reflux
4. 4
   workup.ADDITIONwere added during 10 min
5. 5
   Sonstigeevaporated
6. 6
   Filtrationfiltered through silica gel (deactivated with hexane/Et3N) with hexane

Vorschrift

A solution of 52.45 g (200 mmol) triphenylphosphine in 200 ml CH2Cl2 was treated with 33.16 g (100 mmol) tetrabromomethane (the reaction heated up to reflux) and after 50 min with 32.06 ml (230 mmol) triethylamine (the reaction heated up to reflux and became dark violet). After cooling (0° C.), 12.83 g (50 mmol) of trans-(4-Formyl-cyclohexyl)-methyl-carbamic acid tert-butyl ester in 125 ml CH2Cl2 were added during 10 min. The solution was stirred for 16 h at RT, evaporated and filtered through silica gel (deactivated with hexane/Et3N) with hexane and then hexane/ether 4:1 to 1:1 as eluent to yield 13.28 g (67%) of trans-[4-(2,2-Dibromo-vinyl)-cyclohexyl]-methyl-carbamic acid tert-butyl ester, mp: 93-99° C., dec.; MS: 396 (MH+, 2Br).

Quelle