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A simple and practical protocol for the construction of synthetically important quaternary α-benzyl- and α-allyl-α-methylamino cyclobutanones in good to high yield, via a sequential one-pot methylation/sigmatropic rearrangement, has been accomplished for the first time. The quaternary α-alkyl-α-amino cyclobutanones could be further manipulated, affording synthetically interesting scaffolds such as highly substituted tryptamines and cyclobuta-fused indolines.

The fluorinated half sandwich complex [CpCoLF] (Cp = cyclopentadiene; LF = o-perfluoro-phenylenediimine; 2F) shows a T-shaped geometry with the LF ligand coplanar with the metallocycle. The molecules are dimerized in a head-to-tail fashion and arranged in a herringbone manner in the crystal packing. The crystal structure of 2F is different from that of the corresponding hydrocarbon compound (2H). Moreover, the differences due to the presence of fluorine atoms are also highlighted by the analysis of the intermolecular contacts, which show that 2F exhibits several F⋯F contacts, as well as aromatic intra-dimer π … π interactions in addition to C–H … π and C–H⋯F contacts. No relevant π … π interactions are observed in the case of 2H. Hirshfeld Surface (HS) analysis also depicted well the differences in the solid state interactions between the different crystal structures. In particular, HS has been useful in highlighting the differences observed between the crystal structure of 2H obtained from Rietveld refinement and that measured on single crystal (2HP and 2HSCH, respectively). The effect of the fluorination on the electronic structure has been investigated also by CV measurements and Density Functional Theory calculations. Both are consistent with a lowering in energy of the molecular orbitals. Data Mining Force Field calculations clearly indicate that the 2HSCH structure is more stable than the 2HP one. These findings can be explained in terms of the energy of the intermolecular interactions. The enhanced stability of the fluorine substitute can be easily explained by the large number of strong interactions involving fluorine atoms.

An asymmetric synthesis of α-aryl amino-β-nitro cyclohexanes has been achieved by means of a tandem aza-Michael addition-protonation reaction starting from 1-nitro cyclohexene and anilines. The transformation is proposed to proceed via a transient nitrile enolate which is subsequently stereoselectively protonated by an intramolecular transfer of the proton from nitrogen to the nitronate α-carbon.