Efficient carbene transfer reactivity mediated by Fe(II) complexes supported by bulky alkoxides.

Herein we describe the stoichiometric and catalytic carbene-transfer reactivity of iron(II) alkoxide complexes with iodonium ylide precursors. Treatment of PhIC(COMe) with styrene in the presence of catalytic amounts of several different Fe(OR)(THF) precursors results in efficient cyclopropanation for a variety of styrenes. Computational and reactivity studies suggest a novel remote metallocarbene/vinyl radical intermediate, Fe(OR)(κ-(OC(OMe))C), which could be responsible for the reactive nature of the catalyst.

Simple magnesium alkoxides: synthesis, molecular structure, and catalytic behaviour in the ring-opening polymerization of lactide and macrolactones and in the copolymerization of maleic anhydride and propylene oxide.

The synthesis of two chiral bulky alkoxide pro-ligands, 1-adamantyl--butylphenylmethanol HOCAdBuPh and 1-adamantylmethylphenylmethanol HOCAdMePh, is reported and their coordination chemistry with magnesium(II) is described and compared with the coordination chemistry of the previously reported achiral bulky alkoxide pro-ligand HOCBuPh. Treatment of -butyl--butylmagnesium with two equivalents of the racemic mixture of HOCAdBuPh led selectively to the formation of the mononuclear bis(alkoxide) complex Mg(OCAdBuPh)(THF). H NMR spectroscopy and X-ray crystallography suggested the selective formation of the -symmetric homochiral diastereomer Mg(OCAdBuPh)(THF)/Mg(OCAdBuPh)(THF).

Synthesis, characterization, and alkoxide transfer reactivity of dimeric Tl(OR) complexes.

Reaction of LiOCBuPh with TlPF forms the dimeric Tl(OCBuPh) complex, a rare example of a homoleptic thallium alkoxide complex demonstrating formally two-coordinate metal centers. Characterization of Tl(OCBuPh) by H and C NMR spectroscopy and X-ray crystallography reveals the presence of two isomers differing by the mutual conformation of the alkoxide ligands, and by the planarity of the central Tl-O-Tl-O plane. Tl(OCBuPh) serves as a convenient precursor to the formation of old and new [M(OCBuPh)] complexes (M = Cr, Fe, Cu, Zn), including a rare example of T-shaped Zn(OCBuPh)(THF) complex, which could not be previously synthesized using more conventional LiOR/HOR precursors.