Synthesis and Hydrophosphorylation of pi-Complexes of Esters of Unsaturated Carboxylic Acids with Chromium Subgroup Metals

摘要

Photochemical and thermochemical activation were used to prepare new pi-complexes of chromium,molybdenum and tungsten containing eta~2-and eta~4-coordinated methyl acrylate,methyl cynnamate,and dimethyl fumarate molecules.Geometric,electronic,and energetic parameters of the coordinated ester molecules were found and factors governing eta~2-and eta~4-coordination of the oxodiene system were revealed by nonempirical calculations.Monocarboxylic acid esters incorporated in the 7r-complexes react with dialkyl hydrogen phosphites to give dialkyl acyl phosphites coordinated with the metal center and susceptible to oxidation the corresponding phosphates.In this case,the phosphorylation involves the OH-tautomer of dialkyl hydrogen phosphite.Coordinated dimethyl fumarate undergoes phosphorylation by two concurrent pathways,viz.transesterification or Pudovik reaction.In the latter case,fragmentation of the organometallic compound takes place.