反应详情

Under argon, 8.7 ml of a 1 molar solution of lithium bis-(trimethylsilyl)-amide in THF are added dropwise to a solution, cooled to −78° C., of 1 g (7.9 mmol) of hexahydro-cyclopenta[b]furan-2-one in 20 ml of THF such that the temp. of the mixture does not exceed −65° C. After the addition has ended, stirring is continued at −78° C. for 10 min, and 1.93 g (8.7 mmol) of naphth-2-ylmethyl bromide are then added in one portion. Immediately afterwards, the cooling bath is removed and the mixture is allowed to warm to room temp. After 16 h of stirring at room temp., the mixture is taken up in water/diethyl ether and the aqueous phase is extracted twice with diethyl ether. The combined organic phases are dried over sodium sulphate and then concentrated. The residue is chromatographed over silica gel (mobile phase: dichloromethane); Yield: 1.2 g, colourless oil, diastereomer mixture: 87:13 (Example 1) 1H-NMR (200 MHz; [d6]-DMSO): δ[ppm]=1.2-1.9 (br m,7H), 2.6 (m,1H), 2.87 (dd, 1H); 2.93 (dd,1H), 4.72/4.75 (m;1H), 7.48-7.55 (m;3H), 7.76 (s;1H), 7.81-7.95 (m;3H).

1. customdoes not exceed −65° C
2. additionAfter the addition
3. customImmediately afterwards, the cooling bath is removed
4. stirringAfter 16 h of stirring at room temp.
5. extractionthe aqueous phase is extracted twice with diethyl ether
6. dry with materialThe combined organic phases are dried over sodium sulphate
7. concentrationconcentrated
8. customThe residue is chromatographed over silica gel (mobile phase: dichloromethane)