We’re excited to share our solution to a longstanding challenge in asymmetric catalysis: the enantioselective anti-Michael addition of diverse (hetero)aryl groups to unsaturated carbonyl compounds. As every organic chemistry student learns, organometallic additions to Michael acceptors take place almost universally at the ฮฒ-carbon. Our new Pd-catalyzed reaction overrides this intrinsic selectivity through a unique trans-Pd(Ar)(H) mechanism, delivering aryl groups directly to the ฮฑ-position with up to 99% ee across a broad substrate scope. The key to unlocking this reactivity is (S,S)-(R,R)-PhTRAP, a chiral trans-spanning bisphosphine whose unusually wide bite angle simultaneously suppresses competing hydrodehalogenation and creates a well-defined chiral environment for stereoselection. DFT calculations, reaction kinetics, and organometallic experiments work together to reveal the multi-faceted role of this ligand throughout the catalytic cycle. Congratulations to the whole team, particularly Shenghua Yang, Alena Vasquez, Binh Mai, and Turki Alturaifi, and thank you to our collaborators at the University of Pittsburgh and Bristol Myers Squibb!
๐งช Check out the pre-print in ChemRxiv: https://chemrxiv.org/doi/full/10.26434/chemrxiv.15002500/v1
Molecular Complexity through Catalysis 