Reaktion #53921

Reaktionsgleichung

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

BuLi

DMPU

2-(2-bromoethoxy)tetrahydro-2H-pyran

NH4Cl

→

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

Lösungsmittel

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.DISSOLUTIONdissolved in 20 ml
2. 2
   workup.ADDITIONwere dropped in during 20 min
3. 3
   workup.STIRRINGstirred over night (approx. 16 h)
4. 4
   Extraktionthe mixture was extracted with ether (3×)
5. 5
   WaschenThe organic phase was washed with H2O (2×), aqueous 10% NaCl
6. 6
   Trocknendried with Na2SO4
7. 7
   Filtrationfiltered
8. 8
   Sonstigeevaporated

Vorschrift

A solution of 10.0 g (25.2 mmol) of trans-[4-(2,2-Dibromo-vinyl)-cyclohexyl]-methyl-carbamic acid tert-butyl ester in 400 ml THF was treated at −78° C. with 33.0 ml (68.3 mmol) of BuLi (ca 1.6 M in hexane) and stirred for 2 h, then 27.8 ml (230.4 mmol) of DMPU were added and 10 min later 19.0 ml (125.9 mmol) of 2-(2-bromoethoxy)tetrahydro-2H-pyran dissolved in 20 ml were dropped in during 20 min. The reaction was warmed up to RT and stirred over night (approx. 16 h). An aqueous solution of saturated NH4Cl was added and the mixture was extracted with ether (3×). The organic phase was washed with H2O (2×), aqueous 10% NaCl and dried with Na2SO4, filtered and evaporated to give after flash column chromatography on silica gel (Hexane/EtOAc 19:1 to 3:1) 3.5 g (38%) of trans-Methyl-{4-[4-(tetrahydro-pyran-2-yloxy)-but-1-ynyl]-cyclohexyl}-carbamic acid tert-butyl ester, MS: 366 (MH+).

Quelle