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

Methyl 4,6-O-benzylidene-2,3-bis-O-(PhnMe3−nSnCH2)-α-d-glucopyranosides, (3: n=3; 4: n=2; 5: n=1), prepared from methyl 4,6-O-benzylidene-α-d-glucopyranoside (6) and PhnMe3−nSnCH2I, contain four co-ordinate tin centres in both solution and solid state. Whereas a single molecular arrangement is indicated in solution for 3–5, evidence for several arrangements in the solid state was obtained for each compound from the 119Sn- and 13C-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 solution NMR spectra of 3 and 5 to their attached CH2 groups have been accomplished. The stannacyclic compound, methyl 4,6-O-benzylidene-2,3-bis-O-(2,2-diphenyl-2-stannapropylidene)-α-d-glucopyranoside (7) was similarly prepared from 6, using Ph2Sn(CH2I)2.