Access to central carbon chirality through cycloplatination of 1-(2-pyridinylthio)propanone by cis- PtCl2(S-SOMe(p-tolyl)) . The crystal structure of (SsSc)- Pt{py{SCHC(O)Me}-2}Cl(SOMe(p-tolyl))

• Cycloplatination of the prochiral sp(3)C-H bond of 1-(2-pyridinylthio)propanone (py(SCH2C(O)Me)(-2), 1a) by cis-[PtCl2(SOMe2)] in dry ethanol affords [Pt(py(SCHC(O)Me)-2)Cl(SOMe2)] (3a) in 77% isolated yield without any side product. The same reaction using the chiral complex cis-[PtCl2(S-SOMe(p-tolyl))] (the absolute configuration of sulfur is indicated for the coordinated ligand) leads to two cycloplatinated diastereoisomers, 4a (SsRc) and 4b (SsSc), in 12.9 and 33.7% yield, respectively (de 44.6%). Their absolute configuration was deduced from the analysis of the H-1 NMR spectra and confirmed by an X-ray structural investigation of 4b. Diastereomer 4b was shown to react with PPh3 to give the enantiomer [Pt(py(SCHC(O)Me)-2)Cl(PPh3)] with the central carbon chirality only. Rather surprisingly, attempted cycloplatination Of py(SCH2C(O)Ph)-2 (1b) by cis-[PtCl2(SOMe2)] affords the cycloplatinated complex [Pt(pyf(SCHC(O)Ph)-2)Cl(SOMe2)] (3b) in a miserable yield.

Nyckelord

multidonor ligands

complexes

platinum(ii)

activation

cleavage

oximes

aryl

me

ph

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