Creation of Quaternary Stereogenic Centers via Copper-Catalyzed Asymmetric Conjugate Addition of Alkenyl Alanes to α,β-Unsaturated Cyclic Ketones

Abstract

SimplePhos ligands proved to be very powerful ligands in the generation of quaternary stereogenic centers by Michael addition of alkenyl-aluminum reagents to cyclic enones. Using commercially available and easily accessible alkenylbromides as alane precursors the present procedure offers a facile access to β-alkenyl-substituted cyclohexanones with high enantioselectivities up to 96%

A Chiral Triazole Ligand for Enantiodivergent Catalysis in Asymmetric 1,4‐Addition of Arylboronic Acid

“…Addition of carbon nucleophiles to β-substituted enones stands out as one of the most widespread and dependable methods to address this challenge. [9] Seminal works of the asymmetric Michael addition have been achieved by Feringa, [10] Alexakis [11] and Hoveyda [12] using various highly reactive organo-metallic reagents. However, the impracticality arising from the air and moisture sensitivity of these reagents hindered their widespread application.…”

“…Seminal works of the asymmetric Michael addition have been achieved by Feringa, [10] Alexakis [11] and Hoveyda [12] using various highly reactive organo‐metallic reagents. However, the impracticality arising from the air and moisture sensitivity of these reagents hindered their widespread application.…”

Al(III)-Promoted Formation of All-Carbon Quaternary Centers from Aliphatic Tertiary Chlorides and Alkynyl Silanes

“…Considering the expertise held by one of us concerning organoaluminum reagents and their application within carbon–carbon bond formation processes, − we were prompted to investigate a contemporary perspective on this notably challenging C–C bond formation. Within this context, our involvement in this endeavor, which traces its origins back to Capozzi’s pioneering work in 1982, centers on the coupling of trimethylsilyl alkynes with tertiary alkyl chlorides (Scheme D).…”

Palladium-Catalyzed Asymmetric Conjugate Addition of Arylboronic Acids to α,β-Unsaturated Lactams: Enantioselective Construction of All-Carbon Quaternary Stereocenters in Saturated Nitrogen-Containing Heterocycles

“… 2 Moreover, the incorporation of C(sp 3 ) stereocenters into small-molecule drugs has been correlated with the clinical success of drug candidates. 3 One approach toward synthesizing stereogenic centers is through asymmetric conjugate addition, 4 which can be catalyzed by a wide range of transition metals including copper, 5 manganese, 6 nickel, 7 scandium, 8 and palladium. 9 While many of these methodologies require the use of air- and moisture-sensitive organometallic reagents, strongly basic nucleophiles, or a combination thereof, palladium catalysis enables the use of bench-stable boronic acids and water cosolvents.…”