Conjugate Reduction of α,β-Unsaturated Carbonyl Compounds by Catecholborane

Article abstract of DOI:10.1021/jo00309a007

α,β-Unsaturated ketones which can readily adopt an s-cis conformation undergo conjugate reduction by catecholborane at room temperature. α,β-Unsaturated imides, esters, and amides are unreactive under the same conditions.However, catalytic quantities of Rh(PPh3)3Cl greatly accelerate the 1,4-addition process, effecting conjugate reduction of these substrates by catecholborane at -20 deg C.The resulting boron enolates may be reacted with electrophiles to provide functionalized products.