Synthesis Of Indanones Research Articles

KOtBu Assisted Regio‐ and Stereo‐Selective Alkoxy‐Isomerization of Ortho‐Alkynyl Allylic Alcohols: Synthesis of Alkylidene Dihydroisobenzofurans and Indenones

AbstractA transition metal‐free synthesis of alkylidene dihydroisobenzofurans from the ortho‐alkynyl allylic alcohols is reported herein. Notably, a simple base tBuOK is utilized for the 5‐exo‐dig cyclization and double bond isomerization of ortho‐alkynyl allylic alcohols to furnish alkylidene dihydrobenzofurans with Z‐stereoselectivity under shorter reaction times. In addition, the geometry of the double bonds was confirmed by 1D Selective Gradient NOESY and 2D NMR (NOESY) analysis. Furthermore, the effectuality of the ortho‐alkynyl allylic alcohols has been shown by extending to the one‐pot synthesis of indanones via aqueous acid‐mediated hydrolysis (ring‐opening) of in‐situ formed dihydroisobenzofurans followed by intramolecular condensation reaction under acidic conditions

Hydrogen radical-shuttle (HRS)-enabled photoredox synthesis of indanones via decarboxylative annulation

Hydrogen atom transfer (HAT) process is a powerful and effective strategy for activating C-H bonds followed by further functionalization. Intramolecular 1,n (n = 5 or 6)-HATs are common and frequently encountered in organic synthesis. However, intramolecular 1,n (n = 2 or 3)-HAT is very challenging due to slow kinetics. Compared to proton-shuttle process, which is well established for organic synthesis, hydrogen radical-shuttle (HRS) is unexplored. In this work, a HRS-enabled decarboxylative annulation of carbonyl compounds via photoredox catalysis for the synthesis of indanones is developed. This protocol features broad substrate scope, excellent functional group tolerance, internal hydrogen radical transfer, atom- and step-economy. Critical to the success of this process is the introduction of water, acting as both HRS and hydrogen source, which was demonstrated by mechanistic experiments and density functional theory (DFT) calculations. Importantly, this mechanistically distinctive HAT provides a complement to that of typical proton-shuttle-promoted, representing a breakthrough in hydrogen radical transfer, especially in the inherently challenging 1,2- or 1,3-HAT.

Synthesis of Indanones and Spiroindanones by Diastereoselective Annulation Based on a Hydrogen Autotransfer Strategy.

An unprecedented nickel-catalyzed domino reductive cyclization of alkynes and o-bromoaryl aldehydes is described. The reaction features broad substrate scope and is tolerant of a variety of functional groups, providing straightforward access to biologically significant indanones and spiroindanone pyrrolidine derivatives in good yields with excellent regio- and diastereoselectivity. Preliminary mechanistic studies have shown that indanones are formed by the cyclization of o-bromoaryl aldehydes and alkynes to form indenol intermediates, followed by hydrogen autotransfer.

Synthesis of Indanones and Spiroindanones by Diastereoselective Annulation Based on a Hydrogen Autotransfer Strategy

AbstractAn unprecedented nickel‐catalyzed domino reductive cyclization of alkynes and o‐bromoaryl aldehydes is described. The reaction features broad substrate scope and is tolerant of a variety of functional groups, providing straightforward access to biologically significant indanones and spiroindanone pyrrolidine derivatives in good yields with excellent regio‐ and diastereoselectivity. Preliminary mechanistic studies have shown that indanones are formed by the cyclization of o‐bromoaryl aldehydes and alkynes to form indenol intermediates, followed by hydrogen autotransfer.

ChemInform Abstract: One‐Step Synthesis of Indanones Through NbCl5‐Induced Friedel—Crafts Reaction.

AbstractThis facile protocol allows the synthesis of indanones through Friedel—Crafts reaction of dimethylacrylic acid with toluene and xylenes.

ChemInform Abstract: Superacid‐Promoted Dual C—C Bond Formation by Friedel—Crafts Alkylation/Acylation of Cinnamate Esters: Synthesis of Indanones.

AbstractIn the case of cinnamic esters (I), the indanone is formed by cyclization of the more electron‐rich aryl moiety: arene reactant for (III), (V), (VII)/(VIII) and (IX) or cinnamic ester for (X) and (XII).

Superacid-Promoted Dual C–C Bond Formation by Friedel–Crafts Alkylation/Acylation of Cinnamate Esters: Synthesis of Indanones

Dual C–C bond formation was accomplished in one pot for the synthesis of a wide variety of indanones mediated by triflic acid. The reaction proceeds via an initial Michael-addition-type Friedel–Crafts alkylation followed by intramolecular acylation (cyclization). Significantly, the method was also successfully employed on more reactive β-diarylcinnamates using slightly different conditions.

Regioselective Synthesis of Indanones

The degree of hydrolysis of polyphosphoric acid (PPA) has a crucial effect on the regioselectivity of the PPA-mediated synthesis of indanones. It was found that the regioselectivity can be switched by employing PPA with either a high or low content of P2O5. This methodology was used for the regioselective synthesis of a range of electron-rich indanones, including a natural sesquiterpene.

ChemInform Abstract: Superacid‐Promoted Dual C—C Bond Formation by Friedel—Crafts Alkylation and Acylation of Ethyl Cinnamates: Synthesis of Indanones.

AbstractThe method affords a series of 3‐substituted or 3,3‐disubstituted indan‐1‐ones.

Superacid-Promoted Dual C-C Bond Formation by Friedel-Crafts Alkylation and Acylation of Ethyl Cinnamates: Synthesis of Indanones

A superacid (triflic acid) promoted dual C–C bond formation via intermolecular Friedel–Crafts alkylation (Michael addition type) and intramolecular acylation for the efficient synthesis of 3-substituted indan-1-ones is presented. This method was successful in activating ethyl cinnamates towards dual aromatic electrophilic substitution. Moreover, it enabled us to synthesize novel spirotetracyclic systems.

Synthesis of Indanones via Solid-Supported [2+2+2] Cyclotrimerization

A new facile approach toward natural and unnatural indanones has been developed, featuring a solid-supported [2+2+2] cyclotrimerization as the key step. This strategy has been applied to the chemo- and regioselective assembly of indanone arrays and to the total synthesis of a recently isolated indanone marine natural product.

Synthesis of Indanones via Intramolecular Heck Reaction of Baylis—Hillman Adducts of 2‐Iodobenzaldehyde.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Synthesis of Indanones via Intramolecular Heck Reaction of Baylis-Hillman Adducts of 2-Iodobenzaldehyde

Organic Synthesis Laboratory, School of Chemical Engineering, Hanyang University, Seoul 133-791, KoreaReceived March 4, 2004Key Words : Intramolecular Heck reaction, Baylis-Hillman reaction, Indanone, 2-Iodobenzaldehyde2-Carboalkoxy- and 2-acetyl-1-indanones are importantbuilding blocks in the synthesis of many natural products

One-stage synthesis of indanones in the benzimidazolin-2-one series

The possibility has been shown of a one-stage synthesis of 5,6-ureylene-3-methylindan-1-one and 6,7-ureylene-3,5-dimethylindan-1-one by condensing the corresponding benzimidazolin-2-ones with γ-butyrolactone or crotonic acid in the presence of aluminum chloride. The reaction was performed at a ratio of the reactants benzimidazolin-2-one (5-methylbenzimidazolin-2-one):γ-butyrolactone (crotonic acid):AlCl3=1:1:6. Several derivatives (oximes, semicarbazones, substituted hydrazones) have been obtained that confirm the ketonic structures of the indanones synthesized. The plant growth inhibiting and fungicidal activities of the compounds synthesized have been studied.