[reaction: see text] Eco-friendly direct solvent-free synthesis of flavones is achieved by microwave irradiation of phloroglucinol and beta-ketoesters. Heating with microwaves versus under classical conditions was shown to be higher yielding, cleaner, and faster. The reaction goes through a cycloaddition of an alpha-oxo ketene intermediate followed by an uncatalyzed thermal Fries rearrangement.

A facile synthesis of potential acetylcholinesterase (AChE) inhibitors, the tacrine analogues 3a-p, has been accomplished by direct cyclocondensation of 1-aryl-4-cyano-5-aminopyrazole with β-ketoesters using tin(IV) chloride as catalyst. The structures of all the compounds have been confirmed by IR, ¹H- and ¹³C-NMR.

We present an easy method for the synthesis of β-ketoesters starting from various carbocyclic and heterocyclic carboxylic acids and esters. The β-ketoester side-chain was introduced by a sequence involving α-deprotonation and quenching with CO2, conversion to the corresponding acid chloride and subsequent chain elongation using deprotonated ethyl acetate.

We discovered a highly reactive λ(3)-hypervalent iodane species using an inorganic/organic base for the unorthodox synthesis of amides and ketoesters through grafting terminal alkynes. In contrast to the metal-catalyzed dehydrative approaches the in situ generated nonmetallic reagent efficiently created C-N/C-O and C[double bond, length as m-dash]O bonds with amines/alkynes and water at rt.

Chiral C3-symmetric trisoxazolines are highly efficient stereodirecting ligands in enantioselective Cu(II) Lewis acid catalysis which is based on the concept of a stereoelectronic hemilability of the divalent copper; in direct comparison with the analogous bisoxazoline systems they are more efficient in the enantioselective alpha-amination as well as the enantioselective Mannich reaction of pro...

The intramolecular addition of beta-ketoesters to unactivated alkynes under neutral conditions and at room temperature is described. The method employs triphenylphosphinegold(I) cation as a catalyst for the formation of exo-methylenecycloalkanes. Both monocyclic and bicyclic cyclopentanes and cyclohexanes can be formed in excellent yields and with good diastereoselectivity.

A fluorous cinchona alkaloid ester has been developed as a chiral promoter for the asymmetric fluorination of β-ketoesters. It has comparable reactivity and selectivity to the nonfluorous versions of cinchona alkaloids and can be easily recovered from the reaction mixture by simple fluorous solid-phase extraction (F-SPE) and used for the next round of reaction without further purification.

A ruthenium-catalyzed asymmetric arylation of aliphatic aldehydes and α-ketoesters with arylboronic acids has been developed, giving chiral alkyl(aryl)methanols and α-hydroxy esters in good yields. The use of a chiral bidentate phosphoramidite ligand (Me-BIPAM) achieved excellent enantioselectivities.

A highly enantioselective Michael addition of 1,3-dicarbonyl compounds to nitroalkenes has been developed that employs a newly developed Ni(II)-(bis)diamine based catalyst. The reaction scope includes substituted and unsubstituted malonates, beta-ketoesters, and nitroalkenes bearing aromatic and aliphatic residues. Ease of synthesis of this complex is noteworthy.