Reversible alkoxide .beta.-hydrogen elimination in a homoleptic rhenium alkoxide complex; synthesis of Re3(.mu.-O-iso-Pr)3(O-iso-Pr)6

Abstract

We thank Professor S. Yamamura for a sample of natural daphnilactone A. Supplementary Material Available: Physical properties, NMR spectral data, 13C NMR spectral data, and analytical data for compounds 4, 6, and 9-12 and copies of the NMR spectra of synthetic and natural daphnilactone A (4 pages). Ordering information is given on any current masthead page.

Catalytic selective oxidation of benzyl alcohols to aldehydes with rhenium complexes

“…In view that (a) metal oxo-or peroxo-species formed from the reaction of dioxygen with metal complexes can produce catalytically active oxidants [12,13] and (b) alkoxide clusters containing the Re 3 9+ core can undergo facile ␤-hydrogen elimination at a terminal alkoxide ligand forming a metal hydride complex and the carbonyl compound [14,15], we have examined the possibility of aerobically oxidizing alcohols with the above mentioned system.…”

Rhenium alkoxides

“…For example, in Re 4 O 6 (OMe) 12 , these values are 1.665(8)-1.682(7) and 1.883(7)-1.936(7) Å, respec tively. For example, in Re 4 O 6 (OMe) 12 , these values are 1.665(8)-1.682(7) and 1.883(7)-1.936(7) Å, respec tively.…”

“…The syntheses of Re 4 O 6 (OMe) 12 In the synthesis of Nb 4-x Ta x O 2 (OMe) 14 (ReO 4 ) 2 and Nb 2-x Ta x (OMe) 8 (ReO 4 ) 2 , rhenium reduction is a side re action. When Re 2 O 7 reacts with Nb 2 (OMe) 10 and/or Ta 2 (OMe) 10 , the corresponding bi and trimetallic de rivatives are formed through the addition of rhenium as perrhenate (i.e., without a change in the oxidation state) to the niobium/tantalum alkoxides.…”

“…When electrolysis was carried out in methanol, by varying the process conditions, it was possible to obtain structurally related complexes Re 4 O 6 (OMe) 12 , Re 4 O 2 (OMe) 16 , and Re 4 O 6-y (OMe) 12+y . The role of this process is dictated by the fact that the anodic dissolution of rhenium first gives Re VI derivatives, which are reduced at the cathode to Re V de rivatives, and the ratio of these forms in the electrolyte determines the composition of the crystallization prod uct.…”

“…The role of this process is dictated by the fact that the anodic dissolution of rhenium first gives Re VI derivatives, which are reduced at the cathode to Re V de rivatives, and the ratio of these forms in the electrolyte determines the composition of the crystallization prod uct. The electrolysis in a divided cell (i.e., under conditions sup pressing the cathodic reduction of rhenium derivatives) gave the rhenium(VI) complex Re 4 O 6 (OMe) 12 . 18,22,24, 25 The formation of the rhenium(V) compound, Re 4 O 2 (OMe) 16 , is facilitated by conducting the process in an undivided cell and by an increase in the cathodic current density.…”