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

Methyl 4,6-O-benzylidene-2,3-bis-O-(PhnMe3-nSnCH2)-alpha -D-glucopyranoside s, (3: n = 3; 4: n = 2; 5: n = 1), prepared from methyl 4,6-O-benzylidene-a lpha -D-glucopyranoside (6) and PhnMe3-nSnCH2I, contain four co-ordinate ti n centres in both solution and solid state. Whereas a single molecular arra ngement is indicated in solution for 3-5, evidence for several arrangements in the solid state was obtained for each compound from the Sn-119- and C-1 3-NMR spectra. An X-ray structure determination of 5 indicated the presence of three slightly differing molecular arrangements, and the absence of any intermolecular contacts. Assignments of the individual Sn signals in the s olution NMR spectra of 3 and 5 to their attached CH, groups have been accom plished. The stannacyclic compound, methyl 4,6-O-benzylidene-2,3-bis-O-(2,2 -diphenyl-2-stannapropylidene)-alpha -D-glucopyranoside (7) was similarly p repared from 6, using Ph2Sn(CH2I)(2). (C) 2001 Elsevier Science B.V. All ri ghts reserved.