Conformational analysis of 2,3,5,6-tetrakis(methylene)bicyclo[2.2.2]octanes by circular dichroism.

Synthesis and Circular Dichroism of Optically Pure (±)‐(1S,2S,5S)‐5‐Methoxy‐3,4,6,7‐tetramethylidenebicyclo[3.2.1]oct‐2‐yl Derivatives. Baker's Yeast Reduction of 4‐Methoxy‐5,6,7,8‐tetramethylidenebicyclo[2.2.2]octan‐2‐one

“…4). We had shown, however, for [26] that such a twist was not detected by variable-temperature CD [27]. It is, thus, possible that an other interpretation could apply to explain the observed CD spectra of (-)-I3 and (-)-14.…”

“…216 (9), 201 (3), 187 (4), 186(4). 185 (9), 171 (4), 160(100), 145 (26), 131 (16), 130(32), 129(27), 128(25), 117(28), 115 (66), 105 (53,91 (42).…”

Circular Dichroism of Tricarbonyl(diene)iron Complexes. The Octant Rule Applied to Ketones Perturbed by Remote Fe(CO)3 Groups. Crystal Structure of (±)‐Tricarbonyl[(1RS,4RS,5RS,6SR)‐C5,6,C‐η‐(5,6,7,8‐tetramethylidene‐2‐bicyclo[2.2.2]octanone)]iron

“…The apparent dependence of this spectrum on temperature is too small to allow one to attribute it to a possible equilibrium of conformers. This tetraenone might well be a molecule belonging to a single minimum energy hypersurface as found for 7-deuterium-and 7-methyl-substituted 2,3,5,6-tetramethylidenebicyclo[2.2.2]octanes [5]. The temperature dependence observed for the C D spectrum of (+)-lo (and (-)-lo, Fig.5) could be due to instrumental inaccuracy or/and to solvation and aggregation phenomena [ 141.…”

“…The corresponding ketones 7 and 8 [3] and the deuterated derivatives 5,6, 11, and 12 are also readily available [4]. In a preliminary communication [5], we reported on the optical resolution of these systems. The establishment of their absolute configuration has also been presented [6].…”

“…Oxidative deuteroboration (NaBDJBF,. Et,O) of 1 gave alcohols (+)-S whose optical resolution was accomplished by using Gerluch 's technique [5] [6] (-(-)-4).…”