Convenient Synthesis of Tetrahydro-γ-carbolines and Tetrahydroquinolines through a Chemo- and Regioselectivity Switch by a Brønsted Acid Catalyzed, One-Pot, Multicomponent Reaction
An efficient, one-pot, multicomponentreaction of aldehydes 1, p-methoxyaniline (2a), and 2-vinylindoles 3 was developed. This approach provides a practical approach to synthetically and biologically significant tetrahydro-γ-carboline and tetrahydroquinoline derivatives in good yields through a chemo- and regioselectivity switch, which can be tuned by simply changing the substituent on the indole component
Enantioselective [4+2] Cycloadditions of 2-Vinyl-1 H-indoles with 3-Nitro-2 H-chromenes Catalyzed by a Zn(OTf)2/Bis(oxazoline) Complex: An Efficient Approach to Fused Heterocycles with a Quaternary Stereocenter
There's a ringer: The asymmetric [4+2] cycloaddition reaction of 3‐nitro‐2H‐chromenes with 1‐benzyl‐2‐vinyl‐1H‐indoles catalyzed by Zn(OTf)2 with bis(oxazoline) ligands offers a practical and efficient method to synthesize a variety of fused heterocycles bearing a quaternary stereocenter with good reaction efficiency (up to 94% yield) and excellent stereoselectivities (up to 96% ee, >95:5 d.r.).
A Bronsted acid catalyzed Diels-Alder reaction of 2-vinylindoles and 3-nitrocoumarins has been described. The methodology allows a rapid and expedient synthesis of a variety of coumarin-fused polycyclic indoles in good yields (up to 82%) with high diastereoselectivities (up to >19:1). (C) 2010 Published by Elsevier Ltd.
Brønsted Acid Mediated Tandem Diels−Alder/Aromatization Reactions of Vinylindoles
A Brønsted acid catalyzed tandem Diels−Alder/aromatization reaction of 2-vinylindoles has been developed. The reaction provides a highly efficient and concise approach to 3-indolyl-substituted tetrahydrocarbazoles with various substituents in high yields under mild conditions.
While the presence of sulfur⋅⋅⋅πbonding interaction is a general phenomenon in the biological systems, the exploitation of this noncovalent force in a chemical process yet remains elusive. Herein, we describe the concept of chalcogen⋅⋅⋅πbonding catalysis that activates molecules of π systems through the interaction between chalcogen and π‐electron cloud. The proof‐of‐concept studies using a vinylindole‐based