This review comprises two major parts, which have chiral metal enolates as their focus. In the first part, we discuss transition-metal-catalyzed conjugate additions leading to chiral enolates, which are then subsequently functionalized by reactions with electrophiles, both further catalyzed or uncatalyzed. The second part deals with base-generated enolates and their use in asymmetric transition-metal-catalyzed processes.

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Biological activity, functionality, and synthesis of (fluoro)quinolones is closely related to their precursors (for instance 3-fluoroanilinoethylene derivatives) (i.e., their functional groups, conformational behavior, and/or electronic structure). Herein, the theoretical study of 3-fluoroanilinoethylene derivatives is presented. Impact of substituents (acetyl, methyl ester, and ethyl ester) on the conformational analysis and the spectral behavior is investigated. The B3LYP/6-311++G** computational protocol is utilized. It is found that the intramolecular hydrogen bond N-H···O is responsible for the energetic preference of anti (a) conformer (anti position of 3-fluoroanilino group with respect to the C═C double bond). The Boltzmann ratios of the conformers are related to the differences of the particular dipole moments and/or their dependence on the solvent polarity. The studied acetyl, ethyl ester, and methyl ester substituted fluoroquinolone precursors prefer in the solvent either EZa, ZZa, or both conformers equally, respectively. In order to understand the degree of freedom of rotation of the trans ethyl ester group, B3LYP/6-311G** molecular dynamic simulations were carried out. Vibrational frequencies, electron transitions, as well as NMR spectra are analyzed with respect to conformational analysis, including the effect of the substituent. X-ray structures of the precursors are presented and compared with the results of the conformational analysis.

The reaction of methyl coumalate with a wide range of methylene active compounds, such as keto-esters or keto-sulfones and cyclic or acyclic diketones, afforded more than 30 2,3,5,6-tetrasubstituted 2H-pyrans. The reaction proceeds via a cascade reaction involving a Michael addition-6π-electrocyclic ring opening-proton transfer and 6π electrocyclization, in which a variety of functional groups were tolerated.