Benzylidene acetals of the D-ribonolactones: a structural reassessment
Abstract
The product of the reaction of D-ribono-1,4-lactone with benzaldehyde and concentrated HCl has been shown, by X-ray crystallography of its acetate, to be 3,4-O-(R)-benzylidene-D-ribono-1,5-lactone and not the 3,5-acetal as previously suggested; with ZnCl2 as catalyst the products are 2,3-O-(R)- and -(S)-benzylidene-D-ribono-1,4-lactone the former preponderating.