General approach for the synthesis of polyquinanes
作者:M. Venkatachalam、G. Kubiak、J.M. Cook、U. Weiss
DOI:10.1016/s0040-4039(00)94971-2
日期:1985.1
The diborane-mediated reduction of labile β-diketones 4, 5 and 6 has been employed as the key step in the synthesis of the three polyquinanes, all--tetracyclo-[6.6.0.01,5.08,12]tetradecane 1, all--tricyclo[6.3.0.01,5]undecane 2 and all--tetracyclo-[5.5.1.04,13.O10,13]tridecane, staurane 3, respectively.
The systematic description of planarizing distortions of tetracoordinate carbon is outlined and specifically discussed for C(C)4 moieties which form the central part of fenestranes. Recent synthetic developments of the preparation of stereoisomeric [4.5.5.5]fenestranes and [5.5.5.5]fenestranes are described. Transformations with the aim of increased planarizing distortions are presented. The interaction of Fe2(CO)9 with a fenestradiene led to three structurally well defined Fe-carbonyl complexes.
Planarisation of Tetracoordinate Carbon Atom. A Further Route ot (all-cis)-[5.5.5.5]Fenestrane
作者:Marcel Luyten、Reinhart Keese
DOI:10.1002/hlca.19840670829
日期:1984.12.19
The synthesis of (all-cis)-[5.5.5.5]fenestrane (3) from dicyclopentadiene is reported. Key step is the Pd-catalyzed reductive deoxygenation of an appropriately substituted cyclooctanone, which leads to transannular C,C-bond formation.
The efficient synthesis of all-cis-[5.5.5.5]fenestrane (2) from the readily available intermediate 3 allowed the electron-diffraction analysis of 2. This structure analysis revealed long CC bonds in the central C(C)4 fragment and a twist-envelope conformation for the four cyclopentane substructures. The four bridgehead H-atoms are in a synclinal rather than an ecliptic position with an approximate