Synthesis, solution and solids-state NMR spectra of methyl 4,6-O-benzylidene-2,3-bis-O-(organostannylmethyl)-#alpha#-D-glucopyranosidees Crystal structure of methyl 4,6-O-benzylidene-2,3-bis-O[(dimethylphenylstannyl)methyl]-#lapha#-D-glucopyranoside

摘要

Methyl 4,6-O-benzylidene-2,3-bis-O(Ph_nMe_(3-n)SnCH_2)-#alpha#-D-glucopyranosidese, (3: n = 3; 4: n = 2; 5: n = 1), prepared from methyl 4,6-O-benzyldiene-#alpha#-D-glucopyranoside (6) and Ph_nMe_(3-n)SnCH_2I, contain four co-ordinate tin centres in both solution and solid state. Whereas a single molecular arrangement is indicated in solution for 3-5, evicence for several arrangements in the solids state was obtained for each compound form teh ~119Sn-and ~13C-NMR spectra. An X-ray structure determination of 5 sindicated the presence of three slightly differing molecular arrangements, and the absence of any intermolecular contacts. Asignment so fthe individual Sn signals in the solution NMR spectra of 3 and 5 to their attached CH_2 grouphs have been accomplished. The stannacycic compound, methyl 4,6-O-benzylidene-2,3-bis-O-(2,2-diphenyl-2-stannapropyldiene)-#alpha#-D-glucopyranoside (7) was similarly prepared from 6, using Ph_2Sn(CH_2I)_2.