Synthesis of indanones
Cyclization of electron-rich 2-alkyl-1-ethynylbenzene derivatives was catalyzed by TpRuPPh3(CH3CN)2PF6 in hot toluene to form 1-substituted-1H-indene and 1-indanone products. The cyclization mechanism involves a 1,5-hydrogen shift of an initial metal-vinylidene intermediate.
A. Odedra, S. Datta, R.-S. Liu, J. Org. Chem., 2007, 72, 3289-3292.
Enantioselective synthesis of chiral 3-aryl-1-indanones was achieved through a rhodium-catalyzed asymmetric intramolecular 1,4-addition of pinacolborane chalcone derivatives in the presence of MonoPhos as chiral ligand under relatively mild conditions. This reaction offers an easy access to various enantioenriched 3-aryl-1-indanone derivatives in high yields with excellent enantioselectivities.
Y.-N. Yu, M.-H. Xu, J. Org. Chem., 2013, 78, 2736-2741.
A catalytic amount of SbF5 efficiently converted a mixture of phenylalkynes and aldehydes to indanone compounds in one pot in the presence of EtOH as an additive, and the reaction afforded the corresponding 2,3-disubstituted indanones as a single trans-isomer.
A. Saito, M. Umakoshi, N. Yagyu, Y. Hanzawa, Org. Lett., 2008, 10, 1783-1785.
The combination of In(OTf)3 and benzoic acid synergistically promotes the coupling of alkynes and acetals to form 2,3-disubstituted indanones in excellent yield and diastereoselectivity via a tandem [2 + 2] cycloaddition and Nazarov reaction.
L. Zhu, Z.-G. Xi, J. Lv, S. Luo, Org. Lett., 2013, 15, 4496-4499.
Indanones and 2-cyclopentenones have been successfully prepared in good to excellent yields by the palladium-catalyzed carbonylative cyclization of unsaturated aryl iodides and dienyl triflates, iodides, and bromides, respectively. The mechanism is discussed.
S. V. Gagnier, R. C. Larock, J. Am. Chem. Soc., 2003, 125, 4804-4807.
α-Ammonium acetophenones with an oxidizing C-N bond can serve as substrates for Rh(III)-catalyzed C-H activation under redox-neutral conditions. The coupling with α-diazo esters afforded benzocyclopentanones, and the coupling with unactivated alkenes such as styrenes and aliphatic olefins gave ortho-olefinated acetophenoes. In both systems the reactions proceeded with a broad scope, high efficiency, and functional group tolerance.
S. Yu, S. Liu, Y. Lan, B. Wan, X. Li, J. Am. Chem. Soc., 2015, 137, 1623-1631.
A highly enantioselective carboalkoxylation of alkynes catalyzed by cationic (DTBM-MeO-Biphep)gold(I) complexes enables the synthesis of various optically active β-alkoxyindanone and 3-methoxycyclopentenones derivatives in good yields with high enantioselectivities. The reaction proceeds through an enantioselective cyclization of intermediates containing vinylgold(I) and prochiral oxocarbenium moieties.
W. Zi, F. D. Toste, J. Am. Chem. Soc., 2013, 135, 12600-12601.
A migratory insertion of carbene followed by a Heck reaction enables the synthesis of 2-arylidene-3-aryl-1-indanones in excellent yields from very stable and easily accessible N-tosylhydrazones and 2′-iodochalcones through 5-exo-trig cyclization that delivers the products selectively with E configuration of the double bond. In situ synthesis of both 2′-iodochalcones and N-tosylhydrazones has also been demonstrated.
D. Arunprasath, P. Muthupandi, G. Sekar, Org. Lett., 2015, 17, 5448-5451.
A new palladium(0)-catalyzed three-component reaction of salicylic aldehyde triflates, ethylene glycol vinyl ether, and various secondary nucleophilic amines involving an initial internal Heck arylation, iminium ion formation, and subsequent tandem cyclization gives tertiary 3-aminoindan acetals.
A. Arefalk, M. Larhed, A. Hallberg, J. Org. Chem., 2005, 70, 938-942.
A palladium-catalyzed intramolecular carbonylative annulation with phenyl formate as a CO source enables an efficient synthesis of 2-substituted indene-1,3(2H)-diones from stable and readily available 1-(2-halophenyl)-1,3-diones using K3PO4 as a base and DMSO as a solvent at 95 °C. The reaction offers a broad substrate scope with good to excellent yields.
Y. Zhang, J.-L. Chen, Z.-B. Chen, Y.-M. Zhu, S.-J. Ji, J. Org. Chem., 2015, 80, 10643-10650.
A chiral (1S,2S)-cyclohexanediamine backbone salen-zirconium(IV) complex as the catalyst enables a highly enantioselective α-hydroxylation of β-keto esters using cumene hydroperoxide (CHP) as the oxidant to provide chiral α-hydroxy β-keto esters in excellent yields and enantioselectivities. The zirconium catalyst is recyclable and the reaction can be performed in gram scale.
F. Yang, J. Zhao, X. Tang, G. Zhou, W. Song, Q. Meng, Org. Lett., 2017, 19, 448-451.