Glycal is a name for cyclic enol ether derivatives of sugars having a double bond between carbon atoms 1 and 2 of the ring.
The favoured conformation of this glycal is the half-chair,[6] a result which has been confirmed by quantum mechanical calculations.
Like an alkene, a glycal can undergo electrophilic addition across the double bond to add in these new atoms such as halogens, epoxides, and nitrogen.
D-glucal and radiolabelled D-galactal have been used to selectively bind with amino acids in the active sites of several enzymes.
These enzyme-glycal complexes allow these amino acids that are essential for catalysis to be identified and allow for a better understanding of how these enzymes function.