5.7- Dioxaspiro octane-4.8-dione 6,6-dimethyl

C15H14N2O6 - iy7J-96-iS) see Rosoxacin dimethyl 2,6-dimethoxyterephthalate (Ci2H 40(j 16849-68-6) see Brodimoprim 6,6-dimethyl-5,7-dioxaspiro[2.S]octane-4,8-dione (C]jH)(,04 5617-70-9) see Ketorolac... 

Thermolysis of 6,6-dimethyl-5,7-dioxaspiro[2.5]octane-4,8-dione (31) at 500 °C and 0.05 Torr through a packed silica tube readily affords cyclopropylketene (32) when collected at — 196 °C. On warming to room temperature the ketene dimer, dispiro[2.1.2.1]octane-4,8-dione (33), was obtained in 45% yield. 

Lactones have been converted to (hydroxyalkyljcyclopropyl phenyl ketones on reaction with phenylmagnesium bromide and phenyllithium. Reductive dimerization of ethyl cyclo-propanecarboxylate with sodium gave l,2-dicyclopropylethane-l,2-dione in 69% yield when thionyl chloride treatment was carried out prior to hydrolytic workup, and to dicyclopropyl ketone in 74% yield, when workup included sodium bromate treatment. A related reaction occurred during thermolysis of 6,6-dimethyl-5,7-dioxaspiro[2.5]octane-4,8-dione to give dispiro[2.1.2.1. ]octane-4,8-dione. ... 

Sodium benzenethiolate reacted with 6,6-dimethyl-2-vinyl-5,7-dioxaspiro[2.5]octane-4,8-dione (16) to give the 1,5-addition product only. When ethyl trani-6-(l-heptenyl)-2-oxo-bicyclo[3.1.0]heptane-l-carboxylate (18, R = Et) was treated with potassium benzenethiolate it was converted stereospecifically to the corresponding trawj -cyclopentanone derivative 19 (R = Et) with a defined configuration at the a-carbon atom of the side chain. This reaction proved to be useful for the stereoselective synthesis of prostaglandins. ... 

Dimethyl-5,7-dioxaspiro[2.5]octane-4,8-dione, a highly active cyclopropane compd., allowed to react 11 hrs. at room temp, with aniline product. Y ca. 100%. F. reactions s. S. Danishefsky and R. K. Singh, Am. Soc. 97, 3239 (1975). 

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