作者:Lynne A. Burnett、Philip J. Cox、James L. Wardell
DOI:10.1023/a:1021764521147
日期:——
The synthesis, IR, MS, solution and solid state NMR spectra and X-ray structure of (2,3-O-isopropylidene-5-O-(triphenylmethyl)-alpha-D-ribofuranosyl]triphenylstannane 1 (R3Sn = Ph3Sn) are reported. Compound, 1 (R3Sn = Ph3Sn), crystallizes in the orthorhombic space group C222(1) (Z = 8), with a = 8.935(4), b = 17.058(7), c = 47.94(5)Angstrom. There are two short tin-oxygen separations, at 3.030(7) [involving O4, on an alpha carbon] and 3.094(7) Angstrom [involving O2, on a beta carbon]. Only the O4 atom is considered to form a weak and additional bond to tin; this results in a deviation of the geometry at tin toward trigonal bypramid from tetrahedral, with O4 and C34 in the axial sites [C34-Sn-O4 = 152.3(3)degrees]. The conformation of the ribofuranosyl ring in the solid state is E-o [P, the phase angle of pseudorotation, = 268.4(9)degrees and tau(max), the puckering amplitude, = 38.0(6)degrees], while the isopropylidene ring conformation is between the envelope form, E-C6, and the twist form, T-O3(C6) [P = 46.5(10)degrees and tau(max) = 36.9(6)degrees]. In solution, the ribofuranosyl ring adopts a conformation between E-o and T-1(o).