66129-95-1Relevant articles and documents
Asymmetric Hydrogenation of Unfunctionalized Tetrasubstituted Acyclic Olefins
Bachmann, Stephan,Bigler, Raphael,Denmark, Scott E.,Gosselin, Francis,Han, Chong,Hildbrand, Stefan,Mack, Kyle A.,Pfaltz, Andreas,Scalone, Michelangelo,Shen, Jeff,Tosatti, Paolo,Zhang, Haiming
supporting information, p. 2844 - 2849 (2020/02/05)
Asymmetric hydrogenation has evolved as one of the most powerful tools to construct stereocenters. However, the asymmetric hydrogenation 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 of such olefins and the mechanistic insights of the reaction. The power of this chemistry is demonstrated by the successful hydrogenation of a wide variety of electronically and sterically diverse olefins in excellent yield and high enantio- and diastereoselectivity.
Relative Reactivities of Alkyl-Substituted Alkenes and Cycloalkenes towards Diarylcarbenium Ions
Mayr, Herbert,Pock, Rudolf
, p. 2473 - 2496 (2007/10/02)
The relative reactivities of alkyl-substituted alkenes 4 towards diarylmethyl cations 2 generated in situ from diarylmethyl chlorides 1 and Lewis acids were determined by competition experiments.The relative reactivities were almost independent of the nature of the Lewis acid. Eventual differences of the solvation free enthalpies of various activated complexes are, therefore, independent of the nature of the gegen ions.The rate acceleration by methyl groups - 6-50 by CH3 at the attacked vinylic position and approximately 104 at the developing carbenium centre - indicates a scarcely bridged transition state.