56667-12-0Relevant articles and documents
A donor-acceptor complex enables the synthesis of: E -olefins from alcohols, amines and carboxylic acids
Chen, Kun-Quan,Shen, Jie,Wang, Zhi-Xiang,Chen, Xiang-Yu
, p. 6684 - 6690 (2021/05/31)
Olefins are prevalent substrates and functionalities. The synthesis of olefins from readily available starting materials such as alcohols, amines and carboxylic acids is of great significance to address the sustainability concerns in organic synthesis. Metallaphotoredox-catalyzed defunctionalizations were reported to achieve such transformations under mild conditions. However, all these valuable strategies require a transition metal catalyst, a ligand or an expensive photocatalyst, with the challenges of controlling the region- and stereoselectivities remaining. Herein, we present a fundamentally distinct strategy enabled by electron donor-acceptor (EDA) complexes, for the selective synthesis of olefins from these simple and easily available starting materials. The conversions took place via photoactivation of the EDA complexes of the activated substrates with alkali salts, followed by hydrogen atom elimination from in situ generated alkyl radicals. This method is operationally simple and straightforward and free of photocatalysts and transition-metals, and shows high regio- and stereoselectivities.
Photophysical Properties of Silyl-Substituted Stilbene Derivatives
Maeda, Hajime,Horikoshi, Ryo,Yamaji, Minoru,Furuyama, Taniyuki,Segi, Masahito
supporting information, p. 3410 - 3422 (2020/06/17)
The effects of silyl groups on the structural, absorption, fluorescence, and photoisomerization properties of stilbenes were investigated. In comparison to that of the parent stilbene (1), fluorescence quantum yields (Φf) of Me3Si-substituted stilbenes 2–4 and 6 in solution were higher. Derivative 5, in which Me3Si groups are present at all ortho positions of the arene moieties, did not fluoresce at room temperature. The absorption and fluorescence wavelength maxima of Me3SiMe2Si-substituted stilbene 7 occurred at longer wavelengths compared to those of the Me3Si analog 2. The results of theoretical calculations showed that this difference is a consequence of an increase in the HOMO energy of 7 caused by orbital interaction between π-system and the σ(Si–Si) orbital. Stilbene 14, with two Me3Si-C≡C groups at both para positions, had a high Φf (0.95). The calculated transition dipole moment (μ) was well correlated with Φf. Derivative 21, which contains Ph2N and Me3SiC≡C groups exhibited solvatofluorochromism because it possesses a twisted intramolecular charge transfer (TICT) excited state in which the Ph2N group and the aromatic ring are orthogonal.
Copper-catalyzed double intramolecular ullmann coupling for the synthesis of diastereomerically and enantiomerically pure 4b,9b-dihydrobenzofuro[3,2-b]benzofurans
Imrich, Hans-Georg,Conrad, Jürgen,Beifuss, Uwe
, p. 7718 - 7734 (2015/12/31)
The copper-catalyzed double intramolecular Ullmann coupling of syn-1,2-bis(2-bromoaryl)ethane-1,2-diols with catalytic amounts of CuII oxinate as the copper source, K3PO4 as a base, and KI as a reductant in aqueous acetoni
