what is acetal
A cyclic acetal is an acetal in which the acetal carbon and one or both oxygen atoms are members of a ring. An acetal is a compound that contains two ether groups on the same carbon atom. If the two OH groups are part of a 1,2- or a 1,3-diol, the product is a cyclic acetal. The video below describes how a cyclic acetal is formed from a diol. The purple #color(purple)(O)# atom in the hemiacetal intermediate is held close to the hemiacetal carbon, so the intramolecular ring-closing reaction is fast.