A chiral bis(imidazolidine)pyridine (PyBidine)–Ni(OTf)2 complex smoothly catalyzed an asymmetric Friedel–Crafts reaction of 2-vinylindoles with nitroalkenes to give chiral indoles in a highly enantioselective manner while maintaining the 2-vinyl functionality. The chiral 2-vinylindoles offer unique chiralscaffolds for diverse transformations.
Non‐Bonding Electron Pair versus π‐Electrons in Solution Phase Halogen Bond Catalysis: Povarov Reaction of 2‐Vinylindoles and Imines
作者:Takumi Suzuki、Satoru Kuwano、Takayoshi Arai
DOI:10.1002/adsc.202000494
日期:2020.8.4
The non‐bonding electron pair (n‐pair) of heteroatoms and π‐electrons are both efficient halogen bond (XB) acceptors. In solid and gas phase studies, n‐pairs generally prevail over π‐bonding orbitals as XB acceptors, whereas few studies have been conducted regarding the preference in solution phase. Herein, the Povarovreaction via the C−I⋅⋅⋅N XB interaction and [4+2] cycloaddition via the C−I⋅⋅⋅π
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
A stable, hypervalent cyclic dibenzoiodolium salt acted as a strong halogen bonding (XB)‐donor catalyst for [4+2] cycloaddition of 2‐alkenylindoles, and not as an oxidizing agent. The cross‐[4+2] cycloaddition of 2‐vinylindoles with 2‐alkenylindoles was catalyzed smoothly by the hypervalent cyclic dibenzoiodolium triflate catalyst to give the tetrahydrocarbazoles in up to 99 % yield with 17 : 1 diastereoselectivity
Asymmetric Friedel–Crafts-Type Reaction of 2-Vinylindoles to <i>N</i>-Boc Imines Using a Chiral Imidazolidine-Containing NCN-Pincer Pd Catalyst
作者:Tomoya Yokota、Hyuma Masu、Takayoshi Arai
DOI:10.1021/acs.joc.2c02911
日期:——
A chiral imidazolidine-containing NCN-pincer Pd-OTf complex (NCN-Pd cat) promoted the asymmetric nucleophilicaddition of unprotected 2-vinylindoles to N-Boc imines in a Friedel–Crafts-type manner. The chiral (2-vinyl-1H-indol-3-yl)methanamine products become nice platforms for constructing multiple ring systems.