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Non‐Bonding Electron Pair versus π‐Electrons in Solution Phase Halogen Bond Catalysis: Povarov Reaction of 2‐Vinylindoles and Imines
Author(s) -
Suzuki Takumi,
Kuwano Satoru,
Arai Takayoshi
Publication year - 2020
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.202000494
Subject(s) - chemistry , halogen bond , cycloaddition , catalysis , halogen , heteroatom , phase (matter) , electron , electron pair , photochemistry , computational chemistry , crystallography , organic chemistry , ring (chemistry) , alkyl , physics , quantum mechanics
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 Povarov reaction via the C−I⋅⋅⋅N XB interaction and [4+2] cycloaddition via the C−I⋅⋅⋅π XB interaction were evaluated, revealing that the n‐pair was more dominant in the XB catalysis system in solution. The XB donor‐catalyzed Povarov reaction gave diverse indolyl‐tetrahydroquinoline derivatives in good yields. Synthesis of indolyl‐quinolines was also developed.