Organoboronates represent a cornerstone functional group in modern synthesis owing to their unique reactivity and divergent synthetic capability. Copper catalysis has become one of the most powerful methods to stereoselectively install boron across diverse π-systems. Additionally, this method affords tremendous versatility enabled by difunctionalization of the π-system by the addition of an electrophile. This review covers known electrophiles to intercept catalytic intermediates in borylative difunctionalization strategies that have been reported up to the end of May 2020.

An asymmetric hydroarylative cyclization of enynes involving a C–H bond cleavage is reported. The cobalt-catalyzed cascade generates three new bonds in an atom-economical fashion. The products were obtained in excellent yields and excellent enantioselectivities as single diastereo- and regioisomers. Preliminary mechanistic studies indicate that the reaction shows no intermolecular C–H crossover. This work highlights the potential of cobalt catalysis in C–H bond functionalization and enantioselective domino reactivity.

An enantioselective consecutive cyclization/coupling process, catalyzed by palladium is reported. Stereoinduction arises from an enantioselective carbopalladation, generating an intermediate which promotes a nucleopalladation step. The dual cyclization sequence was compatible with a variety of alkyne‐tethered oxygen‐ and nitrogen‐centered nucleophiles, and a variety of alkenyl‐tethered aryl iodides, to forge numerous bisheterocycles in good yields and high regio‐ and enantioselectivities.

A diastereo-and enantioselective synthesis of boron-containing cyclobutanols is reported. We exploit an enantioselective borylcupration to generate a chiral benzylic copper intermediate that is intercepted with a proximally tethered ketone. The scaffolds contain an all-carbon quaternary center with a modular boronate moiety which allows access to a variety of synthetically valuable functional groups. This work represents an asymmetric approach to monocyclic cyclobutanols and highlights the utility of copper catalysis in the generation of small-sized rings.

An enantioselective borylative cyclization cascade utilizing cyclic imides has been developed. We employ a highly enantioselective borylcupration process that includes a 1,2-addition to a cyclic imide. The products contain a valuable hemiaminal and boronate handle for further elaborations within a congested framework. This work demonstrates the utility of cyclic imides as simple precursors to unlock access to sought-after polycyclic indolines. Futhermore, this report highlights the capability to harness reactive catalytic intermediates to exploit otherwise unreactive functional groups.