The question involves identifying which compounds can be oxidized by periodic acid (\(HIO_4\)). Periodic acid is known to cleave vicinal diols and α-dicarbonyl compounds.
Let's analyze each option:
Compound (A) is a dicarbonyl compound (\(R-C(=O)-C(=O)-R\)). \(HIO_4\) can oxidize this compound by cleaving the bond between the two carbonyl groups.
Compound (B) is a molecule with a vicinal diol (\(R-CH(OH)-CH(OH)-R\)). Periodic acid can oxidize this compound by cleaving between the two hydroxyl groups, forming two carbonyl groups.
Compound (C) is a non-vicinal diol (\(R-CH(OH)-CH_2-CH(OH)-R\)). \(HIO_4\) does not oxidize non-vicinal diols, so this compound will not be affected.
Compound (D) is another vicinal diol (\(R-CH(OH)-CH(OH)-R\)) without any intervening carbon. It can be cleaved by periodic acid similar to compound (B).
Based on this analysis, compounds 1, 2, and 4 are oxidized by \(HIO_4\). Therefore, the correct answer is Option: 1, 2 and 4.
