The bislactones rac-tetrahydro-2, 2Ј-bifuranyl-5,5Ј-dione (rac-12) and its diastereomer meso-25 were prepared from endo- 5-hydroxy-9-oxabicyclo[4.2.1]nonan-2-one (endo-10) and endo-6-hydroxy-9-oxabicyclo[3.3.1]nonan-2-one (endo-11) or exo-5-hydroxy-9-oxabicyclo[4.2.1]nonan-2-one (exo-23), respectively, under the conditions of a Baeyer−Villiger oxidation with trifluoroperacetic acid. The latter compounds were obtained by O-heterocylization of cis,cis-cycloocta-1,5-diene (1) by either reaction with peracids followed by hydrolysis and Jones oxidation or ruthenium tetraoxide oxidation, respectively. The optically active bislactone (R,R)-(−)-12 was prepared in a similar manner from (1S,5R,6R)-(+)-10 and (1R,5R,6R)-(+)-11, which, in turn, were obtained by lipasecatalyzed asymmetric acetylation of the corresponding diols meso-2 and rac-3 and subsequent Jones oxidation of
Anaerobic treatment of Zn(tmeda)Br2, where tmeda denotes N,N,N′,N′‐tetramethylethylenediamine, with a solution of Na(TeAr), sodium aryltellurolate, in ethanol in a 1:2 stoichiometry led to the formation of highly air sensitive Zn(tmeda)(TeAr)2 (1–3), while a 1:1 stoichiometry afforded Zn(tmeda)Br(TeAr) (4). Crystallography revealed all complexes to be monomeric with four coordinate central zinc atoms bound to tmeda and two TeAr, or a TeAr and a Br ligand. Upon mixing two symmetrically substituted Zn(tmeda)(TeAr)2 complexes in solution, 125Te NMR revealed a facile ligand exchange providing Zn(tmeda)(TeAr)(TeAr′). In addition, Zn(tmeda)(TeAr)(TeAr′) complexes form on mixing symmetric Zn(tmeda)(TeAr)2 complexes and (TeAr′)2. The lability of the zinc complexes was put to advantage in ligand‐substitution reactions wherein treatment of SnCl4 with Zn(tmeda)(TeAr)2 affords Sn(TeAr)4 in excellent yields without the concurrent formation of the redox product (TeAr)2. The apparent lability of the Zn–Te bond prevented the volatilization of 1–3 for their use as chemical vapor deposition precursors for the fabrication of ZnTe thin films. On heating, to volatize the complexes, the complexes decompose to cubic ZnTe and TeAr2 sublimes from the samples. Thermal gravimetric analysis indicates the loss of tmeda followed by the loss of TeAr2.
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