O-[(Triorganostannyl)methyl] derivatives of 1,2-O-isopropylidene-α-D-xylofuranose

The synthesis, mass, IR and NMR spectra of 3-O-benzyl-1,2-O-isopropylidene-5-O-[(triphenylstannyl)methyl]-α-D-xylofuranose (9) and 1,2-O-isopropylidene-3-O-(R3SnCH2)-5-O-triphenylmethyl-α-D-xylofuranose (10, R=Bu or Ph) are reported, as is the X-ray structure of10 (R=Ph). Compound10 (R=Ph), crystallizes in the orthorhombic space groupP212121 (Z=4), witha=11.006(4) A,b=17.096(6) A,c=21.164(7) A. The conformation of the furanose ring in solid10 (R=Ph) is a 82∶18 mixture of the envelope (E4) and twist (3T4) forms: the isopropylidene ring conformation is similarly a mixture of envelope and twist forms, with the former dominant. On dissolution, the furanose ring of10 (R=Ph) undergoes a conformation change, with the3T2 conformation becoming the major form. The tin center in10 is four-coordinate and has a tetrahedral geometry.