Water → (RS)-2'-(2-buten-1-yl)-5'-methoxy-2',3'-dihydro-spiro[cyclopentane-1,1'-[1H]indene]-3'-one

Participants

Reaction Steps

A solution of 9.73 g of 5'-methoxy-2',3'-dihydro-spiro[cyclo-pentane-1,1'-[1H]indene]-3'-one, 9.3 ml of 3-buten-2-ol and 100 mg of p-toluenesulfonic acid in 100 ml of 2,2-dimethoxy-propane was boiled under reflux for 90 hours on a water separator filled with molecular sieve (0.4 nm, 2 mm pearl shaped). The reaction mixture was subsequently concentrated in a vacuum and purified by column chromatography on silica gel (hexane/ethyl acetate 7:1). In addition to 4.0 g of educt, there were obtained 6.24 g (51%) of (RS)-2'-(2-buten-1-yl)-5'-methoxy-2',3'-dihydro-spiro[cyclopentane-1,1'-[1H]indene]-3'-one as a yellow oil.

Provenance & Evidence