Modes of Reactivity of Cyclic Diynes: Probing the
<i>syn</i>
/
<i>anti</i>
Selectivity of Tetrathiacycloalkadiynes and Mono(alkyne)cobalt Complexes
作者:Christoph Benisch、Daniel B. Werz、Rolf Gleiter、Frank Rominger、Thomas Oeser
DOI:10.1002/ejic.200390141
日期:2003.3
analogues (8b−8e) in order to probe the reactivity of electron-rich cyclic diynes. Both mono- [B(m.n)] and bis(cyclobutadiene) [C(m.n)] complexes were isolated as products of these reactions and the anti/syn ratio of C(m.n) was determined. For m, n < 4 the syn isomers dominate and this is attributed to the configuration of the intermediate metallacycle which is correlated with the conformations of the
The four-component cyclization of dilithium acetylide with dithiocyanatoalkanes yielded the hitherto unknown tetrathiacyclodiynes 34, 38, 41, and 43 in moderate yields. The use of the trimethylsilyl protecting group allowed a more efficient and flexible stepwise approach with good yields. The resulting tetrathiacyclodiynes 25−44 were investigated by X-ray analysis. For ring systems with a twist-chair
Structural Properties of Bis(hexacarbonyldicobalt) Complexes with Heteroatoms Next to the Former Triple Bonds − A Contribution to the Mechanism of the Pauson−Khand Reaction
作者:Daniel B. Werz、J. Hilko Schulte、Bernhard J. Rausch、Rolf Gleiter、Frank Rominger
DOI:10.1002/ejic.200300862
日期:2004.6
The bis(hexacarbonyldicobalt) complexes of cyclic diynes with sila-, thia- and selena-substituted acetylene units have been isolated. The structural features of these complexes have been elucidated by means of X-ray diffraction analyses on single crystals. In three cases (24′, 25′ and 29′) the X-ray investigations show bis(pentacarbonyldicobalt) complexes instead of bis(hexacarbonyldicobalt) ones.