title: Catalytic Enantioselective Synthesis of Tetrahydocarbazoles and Exocyclic Pictet-Spengler-Type Reactions.
abstract: A synthetic strategy for the synthesis of chiral tetrahydrocarbazoles (THCAs) has been developed. The strategy relies on two types of 6-exo-trig cyclization of 3-substituted indole substrates. Enantioselective domino Friedel-Crafts-type reactions leading to THCAs can be catalyzed by chiral phosphoric acid derivatives (with up to >99% ee), and the first examples of exocyclic Pictet-Spengler reactions to form THCAs are reported.
authors.affiliation: Department of Chemistry, Technical University of Denmark , DK-2800 Kgs Lyngby, Denmark.
authors.forename: Casper L
authors.initials: CL
authors.lastname: Hansen
authors.affiliation: Department of Chemistry, Technical University of Denmark , DK-2800 Kgs Lyngby, Denmark.
authors.forename: Ragnhild G
authors.initials: RG
authors.lastname: Ohm
authors.affiliation: Department of Chemistry, Technical University of Denmark , DK-2800 Kgs Lyngby, Denmark.
authors.forename: Lasse B
authors.initials: LB
authors.lastname: Olsen
authors.affiliation: Department of Chemistry, Technical University of Denmark , DK-2800 Kgs Lyngby, Denmark.
authors.forename: Erhad
authors.initials: E
authors.lastname: Ascic
authors.affiliation: Department of Chemistry, Technical University of Denmark , DK-2800 Kgs Lyngby, Denmark.
authors.forename: David
authors.initials: D
authors.lastname: Tanner
authors.affiliation: Department of Chemistry, Technical University of Denmark , DK-2800 Kgs Lyngby, Denmark.|Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University , Singapore 637551, Singapore.
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Nielsen