Glucopyranose pentachloride

Lemieux32 has pointed out that the preparation by Brig]36 of 3,4,6-tri-0-acetyl-2-0-trichloroacetyl- -D-glucosyl chloride (XXI) through the interaction of penta-O-acetyl-0-D-glucopyranose (XVIII) with phosphorus pentachloride can be rationalized on the basis of modern chemical... 

This reaction has been studied by Abramovitch, who suggested that the phosphorus pentachloride reacts by two mechanisms first, replacement of the 1-0-acetyl group by chlorine and second, chlorination of the 2-0-acetyl group, the chlorine arising from the dissociation of the pentachloride, which cannot therefore be successfully replaced by phosphorus trichloride or thionyl chloride. Penta-0-acetyl-/S-D-glucopyranose was recovered unchanged after refluxing it for four hours with phosphorus trichloride. 

Penta-0-benzoyl-/3-D-glucopyranose or, better, tetra-O-benzoyl-a-D-glucopyranosyl chloride in carbon tetrachloride can be converted at 75° with antimony pentachloride into a mixture of benzoxonium salts that contains 38% of the D-gluco, 25% of the D-manno, 10% of the D-altro, and 20% of the D-ido derivatives these results indicate... 

Octa-O-acetylcellobiose can, likewise, be rearranged by the action of corresponding excesses of aluminum trichloride and phosphorus pentachloride, and thereby gives the heptaacetate of 4-0-j3-d-glucopyranosyl-a-D-altropyranosyl chloride in 40-45% yield. Again, inversion at C-2 and C-3 of the reducing residue is observed. The formation of D-mannose and D-altrose derivatives is observed when penta-O-acetyl-D-glucopyranose is treated with aluminum trichloride-phosphorus pentachloride. ... 

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