494-13-3Relevant articles and documents
Scope and Mechanism of the Ruthenium-Catalyzed Dehydrative C-H Coupling of Phenols with α,β-Unsaturated Carbonyl Compounds: Expedient Synthesis of Chromene and Benzoxacyclic Derivatives
Mokar, Bhanudas Dattatray,Yi, Chae S.
supporting information, p. 4625 - 4632 (2019/12/24)
Chromene and benzoxacyclic derivatives were efficiently synthesized from the ruthenium-catalyzed dehydrative C-H coupling reaction of phenols with α,β-unsaturated carbonyl compounds. The cationic ruthenium-hydride complex was found to be an effective catalyst for the coupling and annulation of phenols with enals to form chromene products. The coupling of phenols with linear enones afforded 2,4-disubstituted chromene derivatives, whereas the analogous coupling with cyclic enones yielded 9-hydroxybenzoxazole products. The reaction of 3,5-dimethoxyphenol with PhCH=CHCDO resulted in the chromene product with a significant H/D exchange to both benzylic and vinyl positions. The most significant carbon isotope effect from the coupling of 3,5-dimethoxyphenol with 4-methoxycinnamaldehyde was observed on the α-olefinic carbon of the chromene product (C(2) = 1.067). A Hammett plot from the coupling of 3,5-dimethoxyphenol with para-substituted p-X-C6H4CH=CHCHO displayed a linear correlation, with a strong promotional effect by an electron-withdrawing group (ρ = +1.5; X = OCH3, CH3, H, F, Cl). Several biologically active chromenone derivatives were synthesized by using the catalytic coupling method. The catalytic method provides an expedient synthetic protocol for the coupling of phenols with α,β-unsaturated carbonyl compounds without employing reactive reagents or forming any wasteful byproducts.
Ring-closing metathesis as a new methodology for the synthesis of monomeric flavonoids and neoflavonoids
Miller, Bradley J.,Pieterse, Tanya,Marais, Charlene,Bezuidenhoudt, Barend C.B.
, p. 4708 - 4710 (2012/09/21)
Basic flavonoid (flavene) and neoflavonoid (neoflavene) skeletons were successfully synthesized using ring-closing metathesis, showing that this methodology can be used as a central synthetic tool for the synthesis of at least two of the three basic flavonoid classes.
Kinetics of the reactions of flavylium ions with π-nucleophiles
Fichtner, Claudia,Remennikov, Grigoriy,Mayr, Herbert
, p. 4451 - 4456 (2007/10/03)
The kinetics of the reactions of the flavylium ion 1a and the 4′-methoxyflavylium ion 1b with various π-nucleophiles and tributylstannane were investigated photometrically in dichloromethane. Electrophilicity parameters E(1a) = -3.46 and E(1b) = -4.96 were derived from the equation log k (20°C) = s(E + N); these allow the prediction of potential reaction partners of the flavylium ions 1a and 1b.
