17 嵩高いシリル基を有するmyo-イノシトール誘導体の環立体配座(口頭発表の部)

概要

論文の詳細を見る
Introduction of bulky silyl protections into 1,2-trans hydroxy groups on a pyranose ring sometimes flips the ring to give a stable chair conformation with more axial substituents (axial-rich form). Such ring-inversion from steric repulsion of the silyl protections has only observed in pyranose rings. We investigated conformational transformation of cyclohexane rings caused by bulky silyl protections. We preliminarily investigated the ring-conformation of 1,2-di-O-trialkylsilyl-cyclohexanediols, 1〜3. X-ray diffraction studies of 1〜3 showed these compounds are all in inverted axial-rich form. The two adjacent bulky silyl protections, therefore, can invert cyclohexane ring to axial-rich form. We then introduced two bulky silyl protections into the adjacent trans hydroxy groups of myo-inositol. When the silyl protections were introduced to C-3 and C-4 hydroxy groups (6p〜8p and 6〜8), the rings maintained the original equatorial-rich chair form. In contrast, among the 4,5-di-O-silylated 11p〜13p and 11〜13, three of them (13p, 12, 13) were flipped to be axial-rich form. Considering the conformation of the 3,4-di-O-silylated compounds, the steric repulsion due to two bulky silyl protections is short to the ring inversion. On the other hand, the rings of some 4,5-di-O-silylated compounds were inverted. In these cases, 1,2-trans-oxgen substituents are in the both sides of the O-silylated positions. If the ring maintained the equatorial-rich conformation, four consecutive equatorial substituents would increase the steric repulsion. To release it, the ring would be flipped. When the bulkiest TBDPS groups were attached to the center of the four 1.2-trans-substituents, the ring was inverted even other hydroxy groups were benzylated.
天然有機化合物討論会の論文
2002-09-01

17 嵩高いシリル基を有するmyo-イノシトール誘導体の環立体配座(口頭発表の部)

スポンサーリンク

概要

著者

関連論文

スポンサーリンク