Reaktion #2144437

Reaktionsgleichung

paraformaldehyde

(+)-Kallolide B

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

BuLi

→

trans-[4-(3-Hydroxy-prop-1-ynyl)-cyclohexyl]-methyl-carbamic acid tert-butyl ester

Ausbeute 79.0%

Lösungsmittel

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeThe following reaction
2. 2
   SonstigeTotal Synthesis of the Pseudopterane (−)-Kallolide B
3. 3
   SonstigeSynthesis of talaromycins A, B, C, and E
4. 4
   Extraktionextracted with water/ether (3×)
5. 5
   WaschenThe organic phases were washed with aqueous 10% NaCl
6. 6
   Trocknendried over Na2SO4
7. 7
   Sonstigeevaporated
8. 8
   SonstigePurification by flash-chromatography on silica gel (hexane/EtOAc 4:1)

Vorschrift

The following reaction was performed in analogy to the reaction described in: Marshall, James A.; Bartley, Gary S.; Wallace, Eli M. Total Synthesis of the Pseudopterane (−)-Kallolide B, the Enantiomer of Natural (+)-Kallolide B. J. Org. Chem. (1996), 61(17), 5729-5735 and Baker, Raymond; Boyes, Alastair L.; Swain, Christopher J. Synthesis of talaromycins A, B, C, and E. J. Chem. Soc., Perkin trans. 1 (1990), (5), 1415-21.). A solution of 993 mg (2.5 mmol) of trans-[4-(2,2-Dibromo-vinyl)-cyclohexyl]-methyl-carbamic acid tert-butyl ester in 20 ml THF was treated at −78° C. with 3.28 ml (5.25 mmol) of BuLi (ca 1.6 M in hexane). After 2 h at this temperature 790 mg (25 mmol) of paraformaldehyde were added. The reaction mixture was warmed up to RT for 3 h and after 1 h at this temperature extracted with water/ether (3×). The organic phases were washed with aqueous 10% NaCl, dried over Na2SO4 and evaporated. Purification by flash-chromatography on silica gel (hexane/EtOAc 4:1) yielded 530 g (79%) of trans-[4-(3-Hydroxy-prop-1-ynyl)-cyclohexyl]-methyl-carbamic acid tert-butyl ester, MS: 268 (MH+).

Quelle