Several novel diimines (Salen-type ligands) 2a–2i and their reduced diamine counterparts 3b,3d–3g and 3i form complexes 4a–4i, 5b,5d–5g, and 5i with PdCl2 in DMF or methanol. Using 1 mol-% of the isolated complexes 4e and 5f many polychlorinated biphenyls (PCBs) can be prepared in moderate to excellent yields according to the Suzuki cross-coupling protocol with contact to air. Several 4-acetylbiphenyls prepared by this method can be converted in moderate yields into the corresponding biphenylcarboxylic acids (BCAs) by alkaline cleavage. An X-ray crystal structure determination confirms the structure of complex 5f.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Four methyl aryl thioethers related to thiamphenicol syntheses and methyl phenyl sulfide were cleanly oxidized into methyl sulfones in high to excellent yields via catalytic green oxidation with aqueous hydrogen peroxide in combination with sodium tungstate. When the same reactions were similarly performed in the absence of the catalyst, the corresponding sulfoxides could be obtained. This viable synthetic approach for the synthesis of DL-threo-thiamphenicol is a simple procedure, which has an economic advantage in view of its application for the large-scale synthesis because it can be carried out under mild conditions.
![Hexanoic acid, 6-[(phenylacetyl)amino]-](http://img.cochemist.com/ccimg/73200/73148-08-0.png)
![Hexanoic acid, 6-[(phenylacetyl)amino]-](http://img.cochemist.com/ccimg/73200/73148-08-0_b.png)
