Hydroxy group interactions in stannylated carbohydrates. Structures and thermal stabilities of 5-deoxy-5-C-(Ph<sub>3</sub>Sn)-1,2-O-isopropylidene-α-<scp>D</scp>-xylofuranose, 5-deoxy-5-C-(IPh<sub>2</sub>Sn)-1,2-O-isopropylidene-α-<scp>D</scp>- and -<scp>L</scp>-xylofuranose, and 5-deoxy-5-C-(I<sub>2</sub>PhSn)-1,2-O-isopropylidene-α-<scp>D</scp>- and -<scp>L</scp>-xylofuranose
作者:Lynne A. Burnett、Vitor F. Ferreira、R. Alan Howie、Helena Rufino、Janet M. S. Skakle、James L. Wardell、Solange M. S. V. Wardell
DOI:10.1039/b204675j
日期:——
Structures and thermal stabilities of 5-deoxy-5-C-(Ph3Sn)-1,2-O-isopropylidene-α-D-xylofuranose, [(D)-3], 5-deoxy-5-C-(IPh2Sn)-1,2-O-isopropylidene-α-D- and -L-xylofuranose, [(D)-4 and (L)-4], and 5-deoxy-5-C-(I2PhSn)-1,2-O-isopropylidene-α-D- and -L-xylofuranose, [(D)-5 and (L)-5], are reported. The hydroxy groups in the stannylated xylofuranose derivatives, 3â5, exhibit roles as Lewis bases, Brønsted acids and hydrogen bonding centres. The 5-deoxy-1,2-O-isopropylidene-α-D- and âL-xylofuran-5-yl ligands operate as C5,O4 chelating ligands (4-membered chelate rings) in 3, C5,O3 chelating ligands in 4
(molecule 2) and 5
(5-membered chelate rings), and a C5,O4,O3 tridentate ligand in 4
(molecule 1)
[both 4- and 5-membered chelate rings]. Compounds 4, in contrast to 3 and 5, undergo slow proton-dephenylation reactions in chloroform solutions at ambient temperature. All decompose on heating at 145â155 °C with evolution of PhH, Me2CO and H2O. The trigonal bipyramidal tin centres in (D)-5 and (L)-5 are chiral, at least in the solid state. Different modes of OâHâO bonding are found in 3, 4
(molecule 2) and 5 compared to that in 4
(molecule 1).
5-deoxy-5-C-(Ph3Sn)-1,2-O-isopropidylene-α-D-xylofuranose, [(D)-3], 5-deoxy-5-C-(IPh2Sn)-1、报告了 5-脱氧-5-C-(I2PhSn)-1,2-O-异亚丙基δ-±-D-和-L-氧基呋喃糖[(D)-4 和 (L)-4],以及 5-脱氧-5-C-(I2PhSn)-1,2-O-异亚丙基δ-D-和-L-氧基呋喃糖[(D)-5 和 (L)-5]。链烷酰化的呋喃木糖衍生物 3â5 中的羟基具有路易斯碱、布氏酸和氢键中心的作用。5-脱氧-1,2-O-异亚丙基δ-D-和α-L-氧杂呋喃-5-基配体在 3 中作为 C5,O4 螯合配体(4 元螯合环)起作用,在 4(分子 2)和 5(5 元螯合环)中作为 C5,O3 螯合配体起作用,在 4(分子 1)中作为 C5,O4,O3 三叉配体起作用[同时具有 4 元和 5 元螯合环]。与 3 和 5 相反,化合物 4 在常温下的氯仿溶液中会发生缓慢的质子-二苯甲基化反应。在 145-155°C 的温度下加热时,所有化合物都会分解,生成 PhH、Me2CO 和 H2O。至少在固态下,(D)-5 和 (L)-5 中的三叉双锥锡中心是手性的。与 4(分子 1)相比,在 3、4(分子 2)和 5 中发现了不同的 OâHâO 成键模式。