Reaktion #53858

Reaktionsgleichung

NH4Cl

1-bromo-3-tetrahydropyranyloxypropane

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

BuLi

→

trans-Methyl-{4-[5-(tetrahydro-pyran-2-yloxy)-pent-1-ynyl]-cyclohexyl}-carbamic acid tert-butyl ester

Ausbeute 42.4%

Lösungsmittel

THF

DMPU

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONwere added over a period of 20 min
2. 2
   Temperaturcooled
3. 3
   workup.ADDITIONpoured
4. 4
   Extraktionextracted (Et2O 3×)
5. 5
   WaschenThe organic phase was washed with aqueous 10% NaCl, water
6. 6
   Trocknendried over Na2SO4
7. 7
   Sonstigeevaporated
8. 8
   Sonstigepurified by flash silica gel column (Hexane/EtOAc 98:2 to 90:10)

Vorschrift

A solution of 3.97 g (10 mmol) of trans-[4-(2,2-Dibromo-vinyl)-cyclohexyl]-methyl-carbamic acid tert-butyl ester in 160 ml THF was treated at −78° C. with 13.13 ml (21 mmol) of BuLi (ca 1.6 M in hexane) and stirred for 2 h. 11 ml DMPU were added and 10 min later 4.60 g (20 mmol) of 1-bromo-3-tetrahydropyranyloxypropane in 15 ml THF were added over a period of 20 min. The reaction mixture was warmed up to RT for 16 h, cooled, poured into cooled aqueous saturated NH4Cl and extracted (Et2O 3×). The organic phase was washed with aqueous 10% NaCl, water, dried over Na2SO4, evaporated and purified by flash silica gel column (Hexane/EtOAc 98:2 to 90:10) to yield 1.61 g (42%) of trans-Methyl-{4-[5-(tetrahydro-pyran-2-yloxy)-pent-1-ynyl]-cyclohexyl}-carbamic acid tert-butyl ester, MS: 378 (M−H).

Quelle