Abstract
<jats:title>Abstract</jats:title> <jats:p> Over the period of 1989–2019, many enantioselective (asymmetric) 1,4‐additions of organoaluminum, Grignard, organozinc and other metals to a wide range of electron‐deficient alkenes have been reported. The resulting enolate is then quenched with H <jats:sup>+</jats:sup> , carbon‐based electrophiles, or non‐carbon‐based electrophiles. This review captures the most selective variants (those delivering 1,4‐addition products with enantiomeric ratios of ≥90:10). The initial enantioselective addition of the organometallic to the 1,4‐acceptor substrate is achieved through the use of copper(I) catalysts, and the enantiofacial selectivity is controlled by an additive (typically a phosphorus‐based ligand) whose coordination to copper also results in a highly ligand‐accelerated reaction. Mechanism‐orientated studies that support this proposal are discussed. The diastereoselectivity of subsequent anion trapping is often more difficult to predict. </jats:p> <jats:p>The substrate scope for 1,4‐addition is presented, and guidelines are given for selecting systems expected to provide high stereoselectivities. Extension of basic methodologies into 1,6‐ (and higher) additions are given, as are protocols for diastereoselective trapping and cascade reactions. All reactions are exemplified in tabularised data, in representative applications of the methodology to important synthetic targets, and in detailed experimental protocols.</jats:p>