The highly efficient asymmetric Michael addition reactions of cyclopentanone with chalcones were catalyzed by a simple and commercially available chiral 1,2-diaminocyclohexane-hexanedioic acid, and exhibited good yields (up to 92%) and excellent enantioselectivities (up to 99% ee). A new di-iminium mechanism for the reaction was proposed.

The C[double bond, length as m-dash]O/C[triple bond, length as m-dash]N stretching vibration arising from a carbonyl/nitrile functional group in various molecular systems has been frequently used to assess, for example, local hydrogen-bonding interactions, among other applications. However, in practice it is not always easy to ascertain whether the carbonyl or nitrile group in question is engag...

We report the synthesis and characterization of a variety of trans-3,4-substituted cyclopentanones and the corresponding tosylhydrazone derivatives starting with diethyl fumarate. Protection of the keto group followed by selective monohydrolysis of esters was achieved, resulting in cyclopentanones with different substituents at positions 3 and 4. The tosylhydrazone derivative of each cyclopenta...

The 12-membered cyclo-penta-[b]indole ring system in the title compound, C13H13NO2, deviates only slightly from planarity (r.m.s. deviation = 0.051 Å). In the crystal, N-H⋯O and O-H⋯O hydrogen bonds link the mol-ecules into sheets parallel to (100). The five-membered cyclopentanone ring is in slightly distorted envelope conformation with the C atom bearing the hydroxy substituent as the flap.

A general approach to asymmetric synthesis of highly substituted spirodihydrocoumarins with a quaternary stereocenter was achieved through neighboring ortho-hydroxyl group induced sequential Michael-lactonization reactions on 2-(2-nitrovinyl)phenols with alkyl cyclopentanone-2-carboxylates in the presence of a catalytic amount of quinine-NH-thiourea followed by p-TSA.

Intramolecular cyclization of (h-diene)Fe(CO)3 complexes bearing a carboxylic acid chloride functionality at the terminal side chain of the diene ligand produces (s, h-allyl)Fe(CO)3 complexes, whereas treatment of the acid chloride complexes with Et3N and AlCl3 provides (h-diene)Fe(CO)3 complexes containing a cyclopentanone moiety. © 2000 Elsevier Science S.A. All rights reserved.

Simulated moving bed (SMB chemical mixtures. This paper presents an almost plug knowledge about the adsorption properties is the basis to control the position of the adsorption and desorption fronts estimated on-line enabling the compensation of initial parameter discrepancies aging or temperature fluctuation. numerical simulation for two case studies relative to the separation of cyclopentanon...

The method of continuous variation in conjunction with 6Li NMR spectroscopy was used to characterize lithium enolates derived from 1-indanone, cyclohexanone, and cyclopentanone in solution. The strategy relies on forming ensembles of homo- and heteroaggregated enolates. The enolates form exclusively chelated dimers in N,N,N',N'-tetramethylethylenediamine and cubic tetramers in tetrahydrofuran a...