Synthesis and physico-chemical characterization of coordination compounds of 3d metals with potassium bicyclo[2.2.1]-hept-5-en-endo-2-oyl-hydroxylamine-3-carboxylate

Summary The ligand, potassium bicyclo[2.2.1]-hept-5-en-endo-2-oyl-hydroxylamine-3-carboxylate-monohydrate, KHL·H₂O₂ and its M(HL)₂ complexes, [{Fe(HL)₂}₂SO₄], K[FeL₂] and K₂[ML₂] (M=Mn^II, Fe^II, Co^II, Ni^II, Cu^II and Zn^II) were prepared and characterized. For all, except the sulphate complex of iron(III), a monomeric octahedral configuration was postulated and this is realized through the coordination of oxygen atoms of the carboxylic, carbonyl and oxime group of two mono-or di-anion ligands. The dianionic form of the ligand is the result of deprotonation of the carboxylic group and mide-alcohol form of the hydroxamic group. For the sulphate-containing iron(III) complex a dimeric coordination is proposed with two monoanions of the organic ligand (the carbonyl oxygens are not coordinated) and the bridging SO₄ group. The relative degree of covalency of the metal-carboxylic oxygen bond is 10.6–45.2% and increases in the order: Mn^IIIIIIIIIIIII. The complexes have been characterized by elemental and t.g. analysis and i.r. spectra.     

Total synthesis of (6Z,9S)-3,4-trans-9-hydroxy-3-methyldodec-cis-6-en-4-olide and (6Z)-3,4-trans-9-oxo-3-methyldodec-cis-6-en-4-olide γ-butyrolactones

The first total synthesis of (6Z,9S)-3,4-trans-9-hydroxy-3-methyldodec-cis-6-en-4-olide and (6Z)-3,4-trans-9-oxo-3-methyldodec-cis-6-en-4-olide was achieved in a convergent pathway. The salient features of our synthesis include Ohira–Bestmann reaction, regioselective alkyne addition to terminal epoxide, TEMPO/BAIB mediated oxidative lactonization, and partial hydrogenation.