Alternate and Efficient Method for the Total Synthesis of Egonol via Sonogashira Coupling Reaction

Abstract

Efficient method for the total synthesis of egonol in five steps via Sonogashira coupling reaction is reported.

One-Pot Tandem Hiyama Alkynylation/Cyclizations by Palladium(II) Acyclic Diaminocarbene (ADC) Complexes Yielding Biologically Relevant Benzofuran Scaffolds

“…The benzofuran compounds constitute important bioactive molecules such as BNC105, amiodarone, cytotoxic flavonoids, and the natural products, namely, daphnodorin A and B , egonol, , and moracin O and P, , and hence, its synthesis by an efficient route is of sufficient interest. − In this regard, the benzofuran derivatives have been successfully prepared by different synthetic approaches − including that of the one-pot tandem C–C bond coupling/cyclization reactions, ,− and for which, we remain interested in exploring the potential of transition-metal complexes of various types of carbene ligands as catalysts for the tandem reactions . As for the first component of the tandem reaction, i.e., the C–C coupling reaction, we became interested in exploring the suitability of Hiyama coupling.…”

Accessing a Biologically Relevant Benzofuran Skeleton by a One-Pot Tandem Heck Alkynylation/Cyclization Reaction Using Well-Defined Palladium N-Heterocyclic Carbene Complexes

“…Finally, the catalyst 1c , as demonstrated through a simple practical synthesis of a benzofuran compound ( 13 ), is an intermediate in the total-synthesis sequence of the bioactive natural product Egonol (Scheme ). , In particular, one-pot tandem Heck alkynylation/cyclization reaction between 4-hydroxy-3-iodo-5-methoxybenzaldehyde (iodovanillin) and 5-ethynylbenzo­[ d ]­[1,3]­dioxole was catalyzed by 1c , yielding the corresponding biologically relevant benzofuran intermediate 13 in DMSO in 36% yield in 4 h of reaction time at 80 °C.…”

“…Benzofurans constitute an important motif ubiquitous in many bioactive compounds like BNC105, amiodarone, cytotoxic flavonoids, and the natural products Daphnodorin A and B, Egonol, , and Moracin O and P. , Hence, an efficient synthesis of benzofuran compounds is of considerable interest. In this context, the one-pot tandem reaction involving sequential Heck alkynylation reaction and intramolecular cyclization provides a step-efficient time-improved approach for construction of the benzofuran framework.…”

Transition Metal Catalyzed Hiyama Cross-Coupling: Recent Methodology Developments and Synthetic Applications

“…The synthesis of biologically relevant benzofuran scaffolds by a convenient route is of huge interest because benzofuran compounds account for important bioactive molecules, including amiodarone [ 210 ], BNC105 [ 211 ], cytotoxic flavonoids [ 212 ], and natural products such as egonol [ 213 , 214 ], daphnodorin A and B [ 215 ] and moracin O and P [ 216 , 217 ]. The application of palladium(II) acyclic diaminocarbene (ADC) complexes in one-pot tandem Hiyama alkynylation/cyclization for synthesizing biologically relevant benzofuran derivatives was disclosed by Singh et al The palladium ADC complexes were synthesized via nucleophilic addition of secondary amines such as morpholine, pyrrolidine, and piperidine to metal precursor cis -{(2,4,6(CH 3 ) 3 C 6 H 2 )NC} 2 PdCl 2 at room temperature that efficiently catalyzed synthesis of benzofuran derivatives.…”