Tin(II) chloride catalyzed reactions of diazodiphenylmethane with vicinal diols in an aprotic solvent. The reactions with cis- and trans-1,2-cyclohexanediols and 1,2-propanediol

2-O-Benzhydryl-3,4-(S)-O-benzyl-idene-d-lyxono-1,4-lactone

X-ray crystallography unequivocally showed that protection of the free hydroxyl group of 3,5-O-benzyl­idene-d-lyxono-1,4-lactone with diphenyl­diazo­methane proceeded with retention of configuration to give the title compound, C₂₅H₂₂O₅. The crystal structure consists of layers of inter­locked mol­ecules lying parallel to the a axis.

2-O-Benzhydryl-3,4-(S)-O-benzylidene-D-xylono-1,4-lactone

X-ray crystallography unequivocally shows that protection of the free hydroxyl group of 3,5-O-benzyl­idene-d-xylono-1,4-lactone with diphenyl­diazo­methane proceeded smoothly to give the title compound, C₂₅H₂₂O₅, with no accompanying epimerization. Unlike the analogously protected lyxono lactone, the isomeric xylono lactone has two mol­ecules present in the asymmetric unit (Z′ = 2). The 5-ring lactones adopt envelope conformations and the 6-ring ketals adopt chair conformations.