Highly enantioselective addition of aliphatic aldehydes to 2-hydroxychalcone enabled by cooperative organocatalysts

Abstract

Herein, we developed an enantioselective addition of aliphatic aldehydes to 2-hydroxychalcone promoted by cooperative organocatalysts, giving access to hybrid flavonoids in excellent enantioselectivities.

Synthesis, Crystal Structure, Hirshfeld Surface Analysis, and Computational Study of a Novel Organic Salt Obtained from Benzylamine and an Acidic Component

“…In the anion part, the phenylmethanamine moiety A (C2−C8/ N1) is planar, having a root mean square (rms) deviation of 0.0148 Å making a dihedral angle of 16.5 (3)°with carboxylate group B (C1/O1/O2). The benzyl group of the anion (C9− C15) is found to be disordered, having two sets of locations with an occupancy ratio of 0.52 (4): 0.48 (4) with reference codes FELDAE (containing the 4-t-butylbenzoate anion) 24 and KALJUF (containing the 3,4-methylenedioxybenzoate anion) 25 are chosen for comparison with A. In the selected crystal structures from the database, the crystal 2.2.…”

“…Use of aldehydes is usually preferred over ketones due to the faster rate of condensation reaction. 4 Schiff bases have azomethine (−HCN) linkage, where the nitrogen atom is sp 2 -hybridized and has a lone pair, which is attributed to the potential biological applications in the fields of pharmacology, anticancer, antibacterial, antifungal, antiviral, antioxidant, and anti-parasitic activities. 5−7 The azomethine nitrogen of the Schiff base may interact with the active sites of the cell components via hydrogen bonding, which is the central point to recognize them as versatile pharmacophores.…”

Controllable Synthesis of Two Isomers 4H-Chromene and 2,8-Dioxabicyclo[3.3.1]nonane Derivatives under Catalyst-Free Conditions

“…2-Hydroxychalcone comprises several reaction sites, and molecules are more flexible than others, which can bind to different biological receptors . These skeletons are types of substrates that can efficiently form bonds as well as different functional molecules via green synthesis . Therefore, 2-hydroxychalcone and 5,5-dimethylcyclohexane-1,3-dione are used as substrates to explore the synthetic strategy for 4 H -chromene and 2,8-dioxabicyclo[3.3.1]­nonane derivatives and their transformational relationship.…”

Asymmetric Synthesis of ent-Fissistigmatin C

“…From a synthetic viewpoint, the stereoselective construction of the pivotal C4–C1′′ linkage constituted the major challenge for the asymmetric synthesis of this type of natural product. Recently, we developed a bioinspired strategy for the synthesis of a hybrid flavonoid driven by visible light and also disclosed a cooperative organocatalyst-promoted enantioselective coupling of aliphatic aldehyde with 2-hydroxychalcone under the irradiation of visible light, which provided a facile solution for the stereoselectivity of our previous work. Herein we accomplished the asymmetric synthesis of fissistigmatins.…”

“…(See the Supporting Information.) Unfortunately, the 5,7-fused ring products 15a , 15b , and 15c were isolated in 20, 23, and 8% yield, respectively as the major products, which resembled fissistigmatin D, a congener of fissistigmatins A–C. The structure of 15 was established by extensive NMR analysis.…”