Novel Synthesis of 3-Phenyl-chromen-4-ones Using N-Heterocyclic Carbene as Organocatalyst: An Efficient Domino Catalysis Type Approach

Abstract

Herein is reported a simple and efficient synthesis of isoflavones starting from various substituted phenacyl bromides and salicylaldehydes in presence of NHC. The mechanism involved domino catalysis type approach with consumption and regeneration of catalyst in two catalytic cycles. This method proved to be very lucrative and gives very good yield. The method described here represents an environmentally benign alternative to classical approach.

Cp*Ir(iii) and Cp*Rh(iii)-catalyzed annulation of salicylaldehydes with fluorinated vinyl tosylates

“…Therefore, more convenient, efficient and sustainable synthetic alternatives for the assembly of chromones from readily available starting materials remain in high demand. 4…”

Recent advances in the synthesis of 4H-chromen-4-ones (2012 − 2021)

“…This NHC catalyst is a non-flammable, inexpensive, biodegradable, non-toxic and metal-ion-free reagent for an environmentally benign approach in the synthesis of 3-aryl-4H-chromen-4-ones. 334 One-pot synthesis of 3-trifluoroethylated 4H-chromen-4-ones was prompted via radical cascade cyclization-coupling reaction of 2-(allyloxy) arylaldehydes using with Langlois' reagent (CF 3 SO 2 Na) employing potassium persulfate as oxidant in DMSO at 80 °C. 335 An enantioselective version for the synthesis of 3-trifluoroethylated/3-difluoroethylated 4H-chromen-4-ones used CF 3 /CF 2 Hsubstituted 2-(allyloxy)arylaldehydes 7 promoted by NHC catalyst 8 and DBU in diethyl ether at room temperature, which after removal of the solvent was treated with molecular iodine and sulfuric acid in DMSO at 150 °C(Scheme 48).…”

Computational and spectral studies of 6-phenylazo-3-(p-tolyl)-2H-chromen-2-one

“…Though several reports have made on the synthesis and applications of various chromenones little work has been done on 3-arylchromen-2-ones [19][20][21]. Benmaktouf et al [22] have carried out the, condensation of p-nitrobenzylcyanide with substituted salicylaldehydes with homogenous catalyst such as piperidine to obtain the corresponding iminocoumarins in moderate yields (10-20%).…”

“…The scaled frequencies in the region 1607-1550 cm -1 (mode No [18][19][20][21][22][23][24]. correspond to the stretching vibrations performed by the aromatic C-C bands with significant PEDs.…”