C-STANNYLATED CARBOHYDRATE-DERIVATIVES .5. 1,2-5,6-DI-O-ISOPROPYLIDENE-3-C-(ORGANOSTANNYL)METHYL-ALPHA-D-ALLOFURANOSE AND 1,2-5,6-DI-O-ISOPROPYLIDENE-3-C-(PHENYLSTANNYL)METHYL-ALPHA-D-ALLOFURANOSE COMPOUNDS - X-RAY CRYSTAL AND MOLECULAR-STRUCTURE OF 1,2-5,6-DI-O-ISOPROPYLIDENE-3-C-(TRIPHENYLSTANNYLMETHYL)-ALPHA-D-ALLOFURANOSE

The crystal structure and the solid state (C-13 and Sn-119) and solution (H-1, C-13 and Sn-119) NMR spectra of 1,2:5,6-di-O-isopropylidene-3-C-triphenylstannylmethyl-alpha-D-allofuranose (1; R = Ph) have been obtained. The structure of compound (1; R = Ph) is similar in both phases and contains a slightly distorted tetrahedral tin atom (C-Sn-C valency angles range from 103.8(3) to 114.9(5)-degrees]. The beta-oxygen atom at C(3) in compound (1; R = Ph) is 3.01 (1) A distant from Sn and is ideally sited to take part in nucleophilic assistance during Ph-Sn bond-cleavage reactions. Reactions of compound (1; R = Ph) and 1,2:5,6-di-0-isopropylidene-3-C-R3Sn-alpha-D-allofuranose with electrophiles (e.g., I2 or CF3CO2H) are also reported.