Synthesis and reactions of functionalized spirocyclopropanes by cyclization of dilithiated β-ketosulfones, α-cyanoacetone and diethyl 2-oxopropylphosphonate with 1,1-diacetylcyclopropane

The cyclization of β-ketosulfone, β-ketonitrile and β-ketophosphonate dianions with 1,1-diacetylcyclopropane afforded 1-hydroxyspiro[5.2]cyclooct-4-en-3-ones, which were transformed, by reaction with tetrabutylammonium halides, into functionalized phenols containing a remote halide function.