Mild Condition for the Deoxygenation of α-Heteroaryl-Substituted Methanol Derivatives

J Org Chem. 2021 Apr 16;86(8):5560-5567. doi: 10.1021/acs.joc.1c00067. Epub 2021 Mar 30.

Abstract

A mild condition via PPh3/I2/imidazole for the deoxygenation of substituted methanol derivatives has been identified. This metal-free process was found to proceed well on secondary or tertiary alcohols substituted with one or two heteroaryl groups, and it tolerates acid-sensitive heterocycles. This condition works for methanol derivatives substituted with 2-pyridyl, 4-pyridyl, or other heterocyclic groups, allowing the negative charge formed during the reaction to resonate to a nitrogen atom. Methanol derivatives substituted with 3-pyridyl or heterocyclic groups that do not allow the negative charge formed during the reaction to resonate to a nitrogen atom will not undergo deoxygenation under this condition.