1,2-versus 1,4-asymmetric reduction of ketones

Abstract

Reduction of α,β-unsaturated ketones generally can give rise to a variety of products, of which chiral allylic alcohols (1,2-reduction) and saturated ketones (1,4-reduction) are the most useful from the synthetic point of view. With the appropriate substitution pattern these processes generate new stereogenic centres, where copper hydride coordinated to chiral ligand provided useful level of enantioselectivity. Attractiveness of the catalytic systems based on Cu(I) owes it to their high catalytic activity, low cost and ability to employ hydrogen or ubiquitous hydrosilanes as stoichiometric reducing reagents. This overview is focused on the efforts directed at developing and refining practical methods to tackle the issues of regio-and enantioselectivity with a particular focus on selective 1,2-and 1,4-manifolds, it mostly covers research published in 2010–2015 referring to earlier works for maintaining continuity.