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Chem 343 – Organic Reactions Chapter 11 Prepared by José Laboy, MS http: www.chem.wisc.edu/areas /clc (Resource page) Reactions of Alcohols #11: Periodate Oxidation of Glycols Mechanism OH
OH
OH
HIO4
O
O
O
O
O
I
O
O
O
H
H2O
H
H2O
OIO3
O
O
O
O
O
O
O
IO3-
O
O
O
O
+
O
O
OH2
I
I
O
I
O
O
O
O
H
I
O
+
OH
OH
O
O
If the initial glycol is trans, i.e., ring structures, it will be difficult to form a cyclic periodate ester intermediate. This reaction is used primarily for identification purposes. This is especially true when carbohydrates are used. See example below. O
O
?
HIO4
C4H10O2
+
H
H
D-Erythrose
Propose a structure for D-­‐Erythrose. Answer OH
HO
D-Erythrose