Sensitivity of <sup>1</sup><i>J</i><sub>C1</sub><sub>-</sub><sub>H1</sub> Magnitudes to Anomeric Stereochemistry in 2,3-Anhydro-<i>O</i>-furanosides
作者:Christopher S. Callam、Rajendrakumar Reddy Gadikota、Todd L. Lowary
DOI:10.1021/jo001747a
日期:2001.6.1
3-anhydro-S-glycosides, the size of the (1)J[C(1)-H(1)] is not sensitive to C(1) stereochemistry. Computational studies on all four methyl 2,3-anhydro-O-furanosides (5-8) demonstrated that (1)J[C(1)-H(1)] was inversely proportional to the length of the C(1)-H(1) bond. A previously reported equation, which relates C(1)-H(1) bond distance and atomic charges to (1)J[C(1)-H(1)] magnitudes, could be used to accurately
在C,(1)和H(1)之间的2,3-脱水-O-呋喃糖苷之间的单键耦合常数的大小已显示对异头中心的立体化学敏感。研究了一组由24种化合物组成的化合物,如果将异头氢反式转化为环氧化物部分,则(1)J [C(1)-H(1)] = 163-168 Hz;而当氢为环氧乙烷环的顺式时,(((1)J [C(1)-H(1)] = 171-174 Hz)。相反,对于2,3-脱水-S-糖苷, (1)J [C(1)-H(1)]对C(1)立体化学不敏感。对所有四种甲基2,3-脱水-O-呋喃糖苷(5-8)的计算研究表明(1 )J [C(1)-H(1)]与C(1)-H(1)键的长度成反比。以前报道的方程式涉及C(1)-H(1)的键距和原子电荷到(1)J [C(1)-H(1)]量级,可用于准确预测α-lyxo(5)和beta-ribo(8)异构体的J值。相反,对于β-lyxo(6)和α-ribo异构体(7),该方程式将这些耦合常数的大小低估了10-20