The selective cross McMurry couplings of diaryl or aryl ketones with various substituted ketones were achieved in 53−94% isolated yields. It is believed that the strong affinity of the substituents to the low-valent titanium surface plays an important role in regards to moderating selectivity. Through the introduction of such substituents followed by their removal post McMurry coupling, structurally
Asymmetric Hydrogenation of Unfunctionalized Tetrasubstituted Acyclic Olefins
作者:Raphael Bigler、Kyle A. Mack、Jeff Shen、Paolo Tosatti、Chong Han、Stephan Bachmann、Haiming Zhang、Michelangelo Scalone、Andreas Pfaltz、Scott E. Denmark、Stefan Hildbrand、Francis Gosselin
DOI:10.1002/anie.201912640
日期:2020.2.10
Asymmetrichydrogenation has evolved as one of the most powerful tools to construct stereocenters. However, the asymmetrichydrogenation of unfunctionalized tetrasubstituted acyclic olefins remains the pinnacle of asymmetric synthesis and an unsolved challenge. We report herein the discovery of an iridium catalyst for the first, generally applicable, highly enantio- and diastereoselective hydrogenation