17244-78-9Relevant articles and documents
Photochemistry of Intramolecular Charge Transfer Excited States in Donor-Acceptor-Substituted Diamines
Wang, Yingsheng,Schanze, Kirk S.
, p. 6876 - 6888 (1995)
The photochemistry and photophysics of 1,2-diamines C5H10NCHPhCHPhNHC6H4R (1, R=CN, and 2, R=4-pyridyl) have been examined.These compounds display a strong absorption band in the near-UV which is due to intramolecular charge transfer from the secondary amine group to the 4-cyanophenyl or (4-pyridyl)phenyl acceptor unit.Photoexcitation into this absorption band leads to moderately intense fluorescence from the 1LE state of the charge transfer chromophore and to homolytic bond fragmentation across the 1,2 C-C bond with moderate quantum efficiency.Detailed photochemical and photophysical studies reveal that the bond fragmentation reaction ensues from a second intramolecular charge transfer excited state (denoted 1CT) which is based on electron transfer from the tertiary piperidine nitrogen to the 4-cyanophenyl or (4-pyridyl)phenyl unit.Photochemical product analysis reveals that erythro -> threo (or threo -> erythro) isomerization occurs under both argon-degassed and air-saturated conditions.This observation indicates that recombination of the radicals formed by bond fragmentation occurs, both within the geminate pair and between free radicals that have escaped the solvent cage.Analysis of fluorescence, transient absorption, and steady-state photochemical kinetics data indicates that (1) internal conversion from the 1LE state to the 1CT state by intramolecular electron transfer occurs with k>/=109 s-1 in all of the diamines; (2) bond fragmentation within the 1CT state occurs with k>/=108 s-1 in each of the diamines; (3) bond fragmentation may be faster in erythro-1 than in threo-1.
Hydrogen Bonding Phase-Transfer Catalysis with Potassium Fluoride: Enantioselective Synthesis of β-Fluoroamines
Pupo, Gabriele,Vicini, Anna Chiara,Ascough, David M. H.,Ibba, Francesco,Christensen, Kirsten E.,Thompson, Amber L.,Brown, John M.,Paton, Robert S.,Gouverneur, Véronique
supporting information, p. 2878 - 2883 (2019/02/14)
Potassium fluoride (KF) is an ideal reagent for fluorination because it is safe, easy to handle and low-cost. However, poor solubility in organic solvents coupled with limited strategies to control its reactivity has discouraged its use for asymmetric C-F
Highly enantioselective Henry reactions of aromatic aldehydes catalyzed by an amino alcohol-copper(II) complex
Qin, Dan-Dan,Lai, Wen-Han,Hu, Di,Chen, Zheng,Wu, An-An,Ruan, Yuan-Ping,Zhou, Zhao-Hui,Chen, Hong-Bin
supporting information, p. 10515 - 10518 (2012/11/07)
Amino alcohol-CuII catalyst: Highly enantioselective Henry reactions between aromatic aldehydes and nitromethane have been developed. The reactions were catalyzed by an easily available and operationally simple amino alcohol-copper(II) catalyst
Planar chiral PHANOLs as double hydrogen bonding donor organocatalysts: Synthesis and catalysis
Braddock, D. Christopher,MacGilp, Iain D.,Perry, Benjamin G.
, p. 1117 - 1130 (2007/10/03)
4,12-Dihydroxy[2.2]paracyclophanediol (PHANOL; 1), and its para-substituted derivatives 2, 5 and 7, were found to catalyse Diels-Alder cyclo-additions of α,β-unsaturated aldehydes or ketones with dienes and/or epoxide ring opening reactions with amines. The mode of catalysis by the PHANOLs is via double hydrogen bonding to the two sp2 lone pairs of a carbonyl group or the two lone pairs of the epoxide. The order of activity of the PHANOLs for catalysis of the Diels-Alder reaction essentially correlates with the expected hydrogen-bond donor strength based on the degree of electron-withdrawing capability of the group(s) in the para position. In contrast, ortho-substituted PHANOLs 10, 11 and 14 were not active as catalysts due to steric interference with the double hydrogen bonding mode. 1H NMR and IR spectral data for the various PHANOLs are discussed in support of the proposed double hydrogen bond mode.
