(2-((3R,5R)-3,5-Bis((tert-butyldimethylsilyl)oxy)cyclohexylidene)ethyl)diphenylphosphine oxide → (4aS,8aS)-4-{(E)-2-[(3R,5R)-3,5-Bis-(tert-butyl-dimethyl-silanyloxy)-cyclohexylidene]-ethylidene}-8-((R)-1,5-dimethyl-5-trimethylsilanyloxy-hex-3-ynyl)-8a-methyl-1,2,3,4,4a,5,6,8a-octahydro-naphthalene

Participants

Reaction Steps

511 mg (0.893 mmol) of carefully dried (3R,5R)-[2-[3,5-bis-(t-butyl-dimethyl-silanyloxy)-cyclohexylidene]-ethyl]-diphenyl-phosphine oxide (Tetrahedron Lett. 32, 7663 (1991)) was dissolved in 5 ml of abs. THF and treated at -78° with 0.65 ml of nBuLi (1.55M, hexane). 15 Minutes later, 179 mg (0.496 mmol) of (4aS,8aR)-5-[(R)-5-trimethylsilanyloxy-1,5-dimethyl-hex-3-ynyl]-4a-methyl-1,2,3,4,4a,7,8,8a-octahydro-naphthalen-1-one, dissolved in 0.5 ml of abs. THF, was added to the deep red solution and kept for 1 h at -78° and for 0.75 h at 0°. The reaction mixture was then poured onto crushed ice/KH2PO4, extracted twice with ether, washed with water and brine, dried over sodium sulfate, and the solvents carefully removed i.V. Flash chromatography (SiO2, hexane/AcOEt=9/1) afforded 108 mg of the title compound as colorless oil, besides 122 mg of recovered ketone in the more polar fractions.

Provenance & Evidence