Synthesis of cyclopentanones
Catalytic amounts of weak bases such as sodium carbonate can carry out the ketonic decarboxylation of adipic acid into cyclopentanone selectively. This is in accordance with a mechanism involving decarboxylation and nucleophilic attack at a second carboxyl group. Stereogenic centres in the β-positions retain their stereochemistry.
M. Renz, A. Corma, Eur. J. Org. Chem., 2004, 2036-2039.
tert-Dodecanthiol-catalyzed generation of acyl radicals and their intramolecular addition to double bonds gave 2-substituted five- and six-membered cyclic ketones in good yields.
K. Yoshikai, T. Hayama, K. Nishimura, K.-I. Yamada, K. Tomioka, J. Org. Chem., 2005, 70, 681-683.
Functionalized α-tertiary and -quaternary 2-arylcycloalkanones are rapidly accessed by scandium(III) triflate-catalyzed diazoalkane-carbonyl homologations. Pairing readily available bis- and tris(oxazoline) based ligands with scandium triflate allows access to arylated medium ring carbocycles with high enantioselectivities and excellent yield.
V. L. Rendina, H. Z. Kaplan, J. S. Kingsbury, Synthesis, 2012, 44, 686-693.
An enantioselective palladium-catalyzed decarboxylative allylic alkylation enables general enantioselective construction of all-carbon quaternary centers on cyclopentanones in yields up to >99% with ee’s up to 94%. Additionally, in order to facilitate large-scale application of this method, a low catalyst loading protocol was developed, using as little as 0.15 mol % Pd, furnishing the product without any loss in ee.
R. A. Craigll, S. A. Loskot, J. T. Mohr, D. C. Behenna, A. M. Harned, B. M. Stoltz, Org. Lett., 2015, 17, 5160-5163.
α-Aryl-α-diazo ketones derived from direct diazo transfer with α-aryl ketones cyclize efficiently in the presence of Rh catalysts to give the corresponding α-aryl cyclopentanones.
D. F. Taber, W. Tian, J. Org. Chem., 2007, 72, 3207-3210.
A combination of visible light photocatalysis and gold catalysis provides an entry into functionalized cyclic ketones from the coupling reaction of alkenyl and allenyl cycloalkanols with aryl diazonium salts via ring expansion-oxidative arylation. A mechanism involving generation of an electrophilic gold(III)-aryl intermediate is proposed.
X.-Z. Shu, M. Zhang, Y. He, H. Frei, F. D. Toste, J. Am. Chem. Soc., 2014, 136, 5844-5847.
A mild and operationally simple visible light mediated photocatalytic arylation/ring expansion of alkenylcyclobutanols in the presence of aryldiazonium salts provides functionalized cyclic ketones.
S. J. Kwon, D. Y. Kim, Org. Lett., 2016, 18, 4562-4565.
A cationic Rh(I)/dppf complex catalyzes the olefin isomerization/allyl Claisen rearrangement/intramolecular hydroacylation cascade of di(allyl) ethers to produce substituted cyclopentanones in good yields under mild conditions.
R. Okamoto, K. Tanaka, Org. Lett., 2013, 15, 2112-2115.
A gold(I)-catalyzed oxidative rearrangement of propargyl alcohols provides an efficient and selective route to 1,3-diketones under mild conditions in the presence of pyridine-N-oxides as external oxidants.
A. S. K. Hashmi, T. Wang, S. Shi, M. Rudolph, J. Org. Chem., 2012, 77, 7761-7767.
A ruthenium-catalyzed hydrative cyclization converts a range of 1,5-enynes bearing terminal alkyne and Michael acceptor moieties into cyclopentanone derivatives.
Y. Chen, D. M. Ho, C. Lee, J. Am. Chem. Soc., 2005, 127, 12184-12185.
A highly enantio- and diastereoselective intramolecular Stetter reaction has been developed. Aliphatic and aromatic aldehydes and a broad range of trisubstituted Michael acceptors have been found to afford the desired products in good overall yield with high enantio- and diastereoselectivity.
J. Read de Alaniz, T. Rovis, J. Am. Chem. Soc., 2005, 127, 6284-6289.
The homologation of arylcyclobutanones with trimethylsilyldiazomethane gives enolsilanes in the presence of Sc(OTf)3 as catalyst with a high preference for methylene migration, whereas Sc(hfac)3 leads to β-ketosilanes. Each adduct affords the cyclopentanone upon hydrolysis.
J. A. Dabrowski, D. C. Moebius, A. J. Wommack, A. F. Kornahrens, J. S. Kingsbury, Org. Lett., 2010, 12, 3598-3601.
Substituted carbocycles, tetrahydrofurans, and tetrahydropyrans can be efficiently obtained from unsaturated carboxylic acids. The methodology involves a Kolbe decarboxylation followed by an intramolecular radical cyclization and a radicalradical cross-coupling process.
F.Lebreux, F. Buzzo, I. E. Markó, Synlett, 2008, 2815-2820.
A stereospecific gold(I)-catalyzed rearrangement of 1-alkynyl cyclobutanols and cyclopropanols provides alkylidene cycloalkanones. The reaction tolerates terminal alkynes as well as alkyl, aryl, and halo-substitution at the acetylenic position and substituents on the ring.
J. P. Markham, S. T. Staben, F. D. Toste, J. Am. Chem. Soc., 2005, 127, 9708-9709.
A simple chiral primary amine catalyses a highly efficient reaction for the synthesis of both Wieland-Miescher ketone and Hajos-Parrish ketone as well as their analogues in high enantioselectivity and excellent yields. This procedure represents one of the most efficient methods for the synthesis of these versatile chiral building blocks even in gram scale with 1 mol% catalyst loading.
P. Zhou, L. Zhang, S. Luo, J.-P. Cheng, J. Org. Chem., 2012, 77, 2526-2530.
Exposure of enynes containing a hydroxyl group at one of the propargylic positions to catalytic amounts of either PtCl2 or (PPh3)AuCl/AgSbF6 results in a selective rearrangement with formation of bicyclo[3.1.0]hexan-3-one derivatives. A total synthesis of the terpenes sabinone and sabinol is described.
V. Mamane, T. Gress, H. Krause, A. Fürstner, J. Am. Chem. Soc., 2004, 126, 8654-8655.
Cu-catalyzed asymmetric conjugate reduction of β-substituted ketones leads to enantiomerically enriched diphenylsilyl enol ethers, which are utilized in a diastereoselective Pd-catalyzed α-arylation of various aryl bromides to yield disubstituted cycloalkanones with excellent levels of enantiomeric and diastereomeric purity. The procedure can be carried out in one-pot.
J. Chae, J. Yun, S. L. Buchwald, Org. Lett., 2004, 6, 4809-4812.