Svyaschenko Y. Functionalized enamines in synthesis of phosphorus containing heterocycles

The thesis is devoted to the development of new accessible methods of synthesizing lambda5-phosphinines and 1,2-lambda5-azaphosphinines by cyclocondensation of phosphorylated derivatives of linear enamines bearing at the beta-position an electron-accepting substituent and a methyl group at the alfa-position. Phosphorylation of beta-dialkylaminocrotonates and beta-dialkylaminocrotonitriles with phosphorus(III) halides was studied. It was found that direction of phosphorylation depends on the nature of the enamine and the phosphorylating agent. The phosphorylation proceeds either at the beta- or beta'-positions of the enamines affording valuable starting materials for the synthesis of phosphorus-containing acyclic compounds, C-phosphorylated and methylene phosphorylated nitrogen-containing heterocycles, and polyfunctionalized benzenes. Two types of phosphahexatriene systems were prepared that were easily transformed into lambda 5-phophinines by [5+1]- or [4+2] cyclocondensations. Synthetic approach by [5+1] cyclocondensation was used for the preparation of hardly accessible 1,2lambda5-azaphosphinines. For the first time it was established that replacement of carbon atom by phosphorus atom at the hexatriene system does not obstruct its ability to electrocyclization.