(3aS,6S,6aS)-6-(tert-butyldimethylsilyloxy)tetrahydrofuro[3,2-b]furan-3(2H)-one → tert-butyldimethyl((3R,3aS,6aR)-6-methylene hexahydrofuro[3,2-b]furan-3-yloxy)silane

Participants

Reaction Steps

A stirred suspension of methyltriphenylphosphonium bromide (1.84 g, 5.16 mmol) and potassium tert-butoxide (578 mg, 5.16 mmol) in tetrahydrofuran (15 mL) was heated at reflux under an atmosphere of argon for 3 hours then allowed to cool to ambient temperature. A solution of ketone (87) (888 mg, 3.44 mmol) in tetrahydrofuran (7.5 mL) was added then heating at reflux continued for 2.25 hours. The mixture was diluted with water (30 mL) then the product extracted into diethyl ether (2×30 mL). The combined organic layers were washed with brine (25 mL), dried (MgSO4), filtered and reduced in vacuo to leave residue (2.07 g). Flash chromatography over silica, eluting with ethyl acetate:heptane mixtures 0:100 to 15:85 gave alkene (88) as a colourless oil (799 mg, 91%).

Provenance & Evidence