反应详情

A solution of 1.6 M n-butyllithium in hexanes (46 mL, 73.6 mmol) was slowly added to a heterogeneous mixture of methyltriphenylphosphonium bromide (28.07 g, 78.6 mmol) in tetrahydrofuran (150 mL) at −10° C. After stirring for 1 h, 1,4-dioxa-spiro[4.5]decan-8-one (8.01 g, 51.3 mmol) was added. After stirring for 3 h, during which time the solution warmed to ambient temperature, acetone was added and the heterogeneous mixture was concentrated. The residue was diluted with 1:1 methylene chloride:ethyl ether, filtered and concentrated. The residue was flash chromatographed with 49:1, 24:1, and 23:2 hexanes:etheyl acetate as the eluant to yield 6.22 g (79% yield) of 8-methylene-1,4-dioxa-spiro[4.5]decane as a yellow oil.

1. stirringAfter stirring for 3 h, during which time the solution
2. concentrationthe heterogeneous mixture was concentrated
3. additionThe residue was diluted with 1:1 methylene chloride
4. filtrationethyl ether, filtered
5. concentrationconcentrated
6. customchromatographed with 49:1, 24:1, and 23:2 hexanes