Caged C-P phosphoranes based on 2-(2-methyl-4-oxopent-2-yloxy)- and 2-[2-(methylcarbonyl)-1-phenoxy]-1,3,2-benzodioxaphospholes and diethyl mesoxalate

Cascade reactions of 2-(2-methyl-4-oxopent-2-yloxy)- and 2-[2-(methylcarbonyl)-1-phenoxy]-1,3,2-benzodioxaphospholes with diethyl mesoxalate yield caged phosphoranes containing a phosphoruscarbon bond: 7,7-bis(ethoxycarbonyl)-3,3,5-trimethyl-1,1-phenylenedioxy- and 7,7-bis(ethoxycarbonyl)-5-methyl-1,1-phenylenedioxy-3,4-benzo-2,6,8,1λ5-trioxaphosphabicyclo[3.2.11.5]octanes. Spatial structure of latter product has been determined by X-ray diffraction analysis.