title: Asymmetric γ-Allylation of α,β-Unsaturated Aldehydes by Combined Organocatalysis and Transition-Metal Catalysis.
abstract: 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 iridium catalyst with a palladium catalyst, the linear allylated products are formed in good yields and excellent regio- and enantioselectivities. The developed method thus provides selective access to all six isomers of the γ-allylated product in a divergent fashion by choosing the appropriate combination of organocatalyst, transition-metal catalyst, and ligand.
authors.affiliation: Department of Chemistry, Aarhus University, 8000 Aarhus C (Denmark).
authors.forename: Line
authors.initials: L
authors.lastname: Næsborg
authors.affiliation: Department of Chemistry, Aarhus University, 8000 Aarhus C (Denmark).
authors.forename: Kim Søholm
authors.initials: KS
authors.lastname: Halskov
authors.affiliation: Department of Chemistry, Aarhus University, 8000 Aarhus C (Denmark).
authors.forename: Fernando
authors.initials: F
authors.lastname: Tur
authors.affiliation: Department of Chemistry, Aarhus University, 8000 Aarhus C (Denmark).
authors.forename: Sofie M N
authors.initials: SM
authors.lastname: Mønsted
authors.affiliation: Department of Chemistry, Aarhus University, 8000 Aarhus C (Denmark). kaj@chem.au.dk.
authors.forename: Karl Anker
authors.initials: KA
authors.lastname: Jørgensen
keywords: allylation; asymmetric catalysis; diastereodivergence; dual catalysis; regiodivergence