反应详情

8.55 g of carefully dried (3R,5R)-[2-[3,5-bis-(t-butyldimethyl-silanyloxy)-cyclohexylidene]-ethyl]-diphenyl-phosphine oxide (Tetrahedron Lett. 32, 7663 (1991)) was dissolved in 90 ml of abs. THF and treated at -78° with 10.9 ml of nBuLi (1.6M, hexane). After 20 minutes, 2.27 g of (S)-5,9-dimethyl-9-trimethylsilanyloxy-decanal, dissolved in a small amount of THF, was added dropwise to the deep red solution. The mixture was kept for 0.5 h at -78° and for 4 h at ambient temperature. After quenching with crushed ice/ KH2PO4, the product was extracted twice with ether, washed with water and brine, dried over sodium sulfate and the solvents removed i.V. Flash chromatography (SiO2, hexane/ AcOEt) yielded in the less polar fractions 3.840 g of (R)-1-[(3R,5R)-3,5-bis-(tert-butyldimethyl-silanyloxy)-cyclohexylidene]-7,11-dimethyl-11-trimethylsilanyloxy-dodec-2-ene, as colorless oil, which was deprotected as described in the following paragraph. 2.40 g of phosphine oxide, which had been used in excess, were recovered in the more polar fractions.

1. additionwas added dropwise to the deep red solution
2. waitThe mixture was kept for 0.5 h at -78° and for 4 h at ambient temperature
3. customAfter quenching with crushed ice/ KH2PO4
4. extractionthe product was extracted twice with ether
5. washwashed with water and brine
6. dry with materialdried over sodium sulfate
7. customthe solvents removed i.V