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The long-sought pathway by which selenocysteyl-tRNA[Ser]Sec is synthesized in eukaryotes has been revealed. Seryl-tRNA[Ser]Sec is O-phosphorylated and SecS, a pyridoxal phosphate-dependent protein, catalyzes the reaction of O-phosphoseryl-tRNA[Ser]Sec with monoselenophosphate to give selenocysteyl-tRNA[Ser]Sec . 1 H- 77 Se HMQC-TOCSY NMR spectroscopy has been developed to detect the selenium-containing amino acids present in selenized yeast after protease XIV digestion. An archived selenized yeast sample is found to contain the novel amino acid S-(methylseleno)cysteine in addition to selenomethionine. Arsenite and selenite react with GSH to form (GS) 2 AsSe−. The structure of this compound has been determined by EXAFS, 77 Se NMR and Raman spectroscopic and chromatographic studies. Its formation under biological conditions has been demonstrated.

The structural investigation of the phosphoroorganic selenium-containing title compound C10H20O6P2Se (1) was carried out. The structure of 1 has been determined by X-ray analysis and correlated with the solid state NMR studies, its purity and identity was confirmed by elemental analysis. The following crystal data were found: triclinic, P1, a = 5.6557(6) A, b = 10.2717(8) A, c = 13.761(1) A, α = 105.580(7)β, p = 90.992(7)°, γ = 101.745(8)°, and Z = 2. Two six-membered rings in the molecule of 1 are in the chair conformation. The selenium atom which bridges the rings is situated axially with respect to both rings. The exocyclic oxygens are, consequently, in equatorial positions.

Stereoselective synthesis of a number of various olefins including functionalized unsaturated compounds based on the S-(β-oxoalkyl) thiophosphates and Se-(β-oxoalkyl) selenophosphates is described.

Synthesis, chemistry and stereochemistry of organo-phosphorus-sulfur(selenium)pseudohalogens are discussed and rationalized.

The interaction of 1,2-aIkadienephosphonic derivatives with phosphorus containing pseudohalogenes affords 2,5-dihydro-1,2-oxaphospholene derivatives. The structure of the new compounds is determined by NMR and IR spectroscopy.

Novel general routes to thiolophosphates 1 and selenophosphates 2 and their application to regio- and stereoselective synthesis of olefins, functionalized olefins and heterofunctionalized dienes-1, 3 is described.

We have previously described regio- and stereospecific synthesis of ally1 selenides I and ally1 sulfides 2 [1]. We now report on the application of 1 and 2 as attractive precursors of new, functionalized: allylic alcohols 3, α-hydroxy ketones 4 and I, 3-dienes 5. 1 and 2 are transformed by oxidation into corresponding ally1 selenoxide and sulfoxide, which display stereospecific [2,3] sigmatropic rearrangement providing after hydrolysis the allylic alcohols 3. Trans configuration of 3 was established by X-ray analysis. In some cases the rearrangement is accompanied by elimination giving the 1,3-dienes 5. Compounds 3 and 5 can be easily separated by column chromatography Dephosphorylation of 3 afforded the α-hydroxy ketones 4.

Ring opening reactions involving various heterocycles, the Schwartz reagent [Cp2ZrHC1]n and a number of chlorophosphines or phosphenium salts will be presented. Scope and limitations of this useful methodology will be discussed.

Interaction between some 1,2-alkadienephosphonic derivatives and dimethyl(diisopropyl)phosphonic sulfenyl chlorides in weak polar media was investigated. We established that in all cases the oxaphospholic cyclization of 1,2-alkadienephosphonic system took place, and 4-thiodi-alkoxyphosphonyl-2,5-dihydro-l,2-oxaphospholic derivatives were obtained.