Melinda Sipos

Diastereoselective synthesis of 1,2,3,6-tetrahydrophosphinine 1-oxides with an exocyclic P-function by a Michael type addition

The anions generated from diphenylphosphine oxide or dialkyl phosphites add easily at the α,β-double-bond of 1,2-dihydrophosphinine oxides 1 to afford a single diastereomer of 3-substituted tetrahydrophosphinine oxides 2–4 existing in a twist-boat conformation.

Intra- and intermolecular interactions and water pincer in the crystal structure of a 3-P(O)Ph2 substituted 1,2,3,6-tetrahydrophosphinine oxide hydrate

Single crystal X-ray structure analysis of 3-diphenylphosphinoxido-1-phenyl-4-chloro-1,2,3,6-tetrahydrophosphinine oxide (1)·H2O provided experimental proof for a transannular PO⋯HC type interaction. The embedded water molecule bridges two PO groups of the P-heterocycle via intra-associate hydrogen bonds. Theoretical calculations showed that the conformation of the hetero-ring alters only slightly due to the presence of the water molecule. Thus 1 behaves as a preorganized host molecule for water, presenting a minimum ring-size molecular environment for water binding.

Synthesis of 1‐Aryl‐1,2,3,4,5,6‐hexahydrophosphinine 1‐Oxides

Abstract Possibilities for the synthesis of 1‐(2,4,6‐triisopropylphenyl‐)1,2,3,4,5,6‐hexahydrophosphinine oxide (2) have been explored. The trivial method based on the hydrogenation of the corresponding dihydrophosphinine oxides (8a–e) was suitable only for the preparation of hexahydrophosphinine oxides containing a trimethylphenyl or methylphenyl group on the phosphorus atom (9a–c). The triisopropylphenyl product (2) was synthesized by the stepwise reduction of the double bonds of starting material 1. Hence, the ring contraction side reaction, observed during the catalytic hydrogenation, could be eliminated. The unusual reactivity was studied by quantum chemical calculations.

Novel Heterocyclic P-Ligands: Synthesis and Application in Pt(II) Complexes

3-Diphenylphosphino-1,2,3,6-tetrahydro- and 1,2,3,4,5,6-hexahydro-phosphinines, as well as dibenzo[c,e][1,2]oxaphosphorines (L) were prepared and used in the synthesis of the corresponding cis chelate Pt(II) complexes and PtCl2L2 complexes, respectively. The latter family of compounds includes 7-membered ring Pt(II) complexes.