Organocatalytic asymmetric strategies to carbocyclic structures by γ-alkylation-annulation sequences
作者:Bjarke S. Donslund、Kim Søholm Halskov、Lars A. Leth、Bruno Matos Paz、Karl Anker Jørgensen
DOI:10.1039/c4cc06556e
日期:——
carbocyclic structures are accessed via a highly regio- and enantioselective aminocatalytic gamma-addition of cyclic enals to vinyl phosphonates followed by a one-pot intramolecular Horner-Wadsworth-Emmonsreaction. It is also demonstrated that nitro olefins can act as electrophiles in a similar reaction concept, providing carbocycles in equally high stereoselectivity.
Asymmetric γ-Allylation of α,β-Unsaturated Aldehydes by Combined Organocatalysis and Transition-Metal Catalysis
作者:Line Naesborg、Kim Søholm Halskov、Fernando Tur、Sofie M. N. Mønsted、Karl Anker Jørgensen
DOI:10.1002/anie.201504749
日期:2015.8.24
The first asymmetric regio‐ and diastereodivergent γ‐allylation of cyclic α,β‐unsaturated aldehydes based on combined organocatalysis and transition‐metal catalysis is disclosed. By combining an aminocatalyst with an iridium catalyst, both diastereomers of branched allylated products can be achieved in moderate to good yields and excellent regio‐ and stereoselectivities. Furthermore, by replacing the
Enantioselective Oxidative Coupling of Carboxylic Acids to α-Branched Aldehydes
作者:Lars A. Leth、Line Næsborg、Gabriel J. Reyes-Rodríguez、Henriette N. Tobiesen、Marc V. Iversen、Karl Anker Jørgensen
DOI:10.1021/jacs.8b07394
日期:2018.10.10
organocatalysis is proposed to account for the coupling of carboxylicacids to α-branched aldehydes by combining primary amine catalysis and an oxidant. The developed methodology is an enantioselective α-coupling of aromatic and aliphatic carboxylicacids to α-branched aldehydes and proceeds in high yields (up to 97%) and for most examples good enantioselectivities (up to 92% ee). On the basis of experimental and
Catalytic Asymmetric Oxidative γ-Coupling of α,β-Unsaturated Aldehydes with Air as the Terminal Oxidant
作者:Line Naesborg、Vasco Corti、Lars Astrup Leth、Pernille H. Poulsen、Karl Anker Jørgensen
DOI:10.1002/anie.201711944
日期:2018.2.5
A novel concept for catalytic asymmetric coupling reactions is presented. Merging organocatalysis with single‐electron oxidation by using a catalytic amount of a copper(II) salt and air as the terminal oxidant, we have developed a highly stereoselective carbon–carbon oxidative coupling reaction of α,β‐unsaturated aldehydes. The concept relies on the generation of a dienamine intermediate, which is