Stereoselective Hydrogen Atom Transfer in Free Radical Reactions

Abstract Hydrogen atom transfer (HAT) is one of the important class of radical reactions. Although extensive research into this elementary step has resulted in the discovery of many compounds capable of functioning as HAT reagents, synthetic methods available to control the stereoselectivity of the HAT process remains challenging. This mini review outlines how small molecule chiral HAT reagents and catalysts were used to achieve stereoselectivity (diastereoselectivity and enantioselectivity) in free radical reactions. The review also focuses on the recent surge in photoenzymatic catalysis to achieve efficient HAT reactions.