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1,4-Bipolar substrates of type (I) and (IV) having an acidic CH2-group react with internal alkynes (II) to produce naphthalenes or polyfunctionalized benzenes, resp., containing a -CF2-X group.

The process takes place with high regioselectivity to produce fused heterocyclic chlorides (III).

The novel target compounds (IV) can also be obtained via ring closure of dichloride (I) followed by treatment with the Grignards.

Addition of secondary amines to alkynylphosphonates catalyzed by Cu(I) salts proceeds regio- and stereospecifically to form ( E )-2-(dialkylamino)alkenylphosphonates. The E -configuration was proved by analysis of 13 C– 31 P vicinal spin–spin coupling constants in the NMR spectra of the products and authentic model compounds. The 3 J PC constants in the model compounds fall in the range of 6–12 Hz for the cis arrangement of the coupled nuclei and are equal to or higher than 16 Hz for the trans configuration. Related coupling constants in the addition products are around 5 Hz, that is, corresponding to cis coupling.

Diethyl 3,3,3-trifluoroprop-1-ynylphosphonate and diethyl 3,3,4,4,4-pentafluorobut-1-ynylphosphonate are obtained by the dehydration of the corresponding enols using P2O5–Et3N system as a dehydrating agent, affording acetylenes in 50–60% yield. By the reaction of these perfluoroacetylenephosphonates with acyclic and cyclic 1,3-dienes or diene-like heteroaromatic and aromatic compounds corresponding Diels–Alder cyclo- and bicycloadducts were prepared in good yields (65–90%). The reactivity of the dienes and acetylenes which depends on their structure, as well as the regioselectivity of the reaction are established.

Comprehensive studies of photoinduced addition of phosphorus trihalides to unsaturated compounds, i.e. alkenes, alkynes, alkadienes, and enynes, were carried out. The addition of phosphorus trihalides to unsaturated C‒C bonds is proved to be a radical chain process, the total reaction irate increasing with the increase of electron density on the unsaturated C‒C bond. The photoinduced reaction of alkenes with PRr3 goes via Br atom attack on the least substituted C-atom of an unsaturated C‒C bond and mainly results in the formation or dibromophosphines with a phosphorus atom in the second position of the carbon chain −(1–2)-addition. In the case of polysubstituted alkenes an alternative direction of the reaction is realized, namely the photoinduced substitutional dibromophosphination to alkyl group. The reaction with alkynes results only in the formation of the products of (1–2)-addition. The Regioselectivity of the addition of phosphorous trihalide fragments to the substrate containing a heteroato...

Arbusov reaction of trialkyl phosphites with haloalkynes opened a new route to the synthesis of acetylenic phosphonates as well as attracted the investigators attention to the nucleoohilic substitution of halogene at sphybridized carbon atoms. The most important compounds of this type are chloro- and bromoethyne phosphonates formed by the action of dihaloethynes upon phosphites. These polyfunctional compounds may interact via triple bond opening and/or halogene substitution. The latter pathway results in the formation of different phosphonates and diphosphonates (1)