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An enantioselective tandem sequence that comprises a cycloaromatization process followed by an intramolecular desymmetrizing Friedel‐Crafts alkylation of functionalized cyclohexadienones has been accomplished. The process takes place in good yields (65–95%), with excellent diastereoselectivity (>20:1) and enantiomeric ratios up to 90.5:9.5 in the presence of (R)‐BINOL‐derived N‐triflyl phosphoramides, and it gains access to a family of pyrrolo[2,1‐a]isoquinoline derivatives in a simple manner, with the simultaneous generation of two vicinal stereocenters, one of them a tetrasubstituted carbon stereocenter. [ABSTRACT FROM AUTHOR]

Four complexes of essential metal ions, Cu(II) and Ni(II), with the new sulfonamide ligand N-(pyridin-2-ylmethyl)quinoline-8-sulfonamide (HQSMP) were synthesized and physicochemically and structurally characterized. Complex [Cu(QSMP)Cl]n (2) consists of a polymeric chain formed by distorted square pyramidal units. In 2, the sulfonamide ligand acts as a bridge coordinating to one Cu(II) through its three N atoms and to another metal ion via one O atom in the sulfonamido group, while the pentacoordinate complex [Cu(QSMP)(C6H5COO)] (3) presents a highly distorted square pyramidal geometry. Complex [Ni(QSMP)(C6H5COO)(CH3OH)][Ni(QSMP)(CH3COO)(CH3OH)] (4) consists of two mononuclear entities containing different anion coligands, either a benzoate or an acetate group. Both units exhibit a distorted octahedral geometry. The interaction of the complexes with CT-DNA was studied by means of UV-Vis and fluorescence spectroscopy, interestingly revealing that the Ni(II) complex presents the highest affinity towards the nucleic acid. Complexes 1 and 2 are able to cleave DNA. Both compounds show promising nuclease activity at relatively low concentrations by mediating the production of a reactive oxygen species (ROS). The interaction of the four complexes with bovine serum albumin (BSA) was also investigated, showing that the compounds can bind to serum proteins. The antitumor potential of complexes 1 and 2 was evaluated against the A549 lung adenocarcinoma cell line, revealing cytotoxic properties that were both dose- and time-dependent. [ABSTRACT FROM AUTHOR]

Dicyanoalkenes are versatile reagents in organic synthesis and they have been extensively used in a wide variety of organic transformations. However, their reactivity towards fluorinated imines remained almost unnoticed. The divergent reactivity of fluorinated conjugated sulfinyl imines with dicyanoalkenes is described herein. On the one hand, when tert‐butyl sulfinyl imines were employed, a cycloaromatization cascade process took place preferentially, rendering valuable trifluoromethyl arenes. On the other hand, the reaction with p‐tolyl sulfinyl imines mainly led to a complex tetracyclic skeleton, involving an azetidinimine rearrangement of a reaction intermediate. Finally, when 1‐indanone‐derived dicyanoalkenes were employed, the aromatization process was interrupted, rendering a new family of diene derivatives. Theoretical calculations were performed in order to shed light on the mechanistic outcome of this transformation. [ABSTRACT FROM AUTHOR]

The asymmetric intramolecular aza‐Michael reaction (IMAMR) is a very convenient strategy for the generation of heterocycles bearing nitrogen‐substituted stereocenters. Due to the ubiquitous presence of these skeletons in natural products, the IMAMR has found widespread applications in the total synthesis of alkaloids and biologically relevant compounds. The development of asymmetric versions of the IMAMR are quite recent, most of them reported in this century. The fundamental advances in this field involve the use of organocatalysts. Chiral imidazolidinones, diaryl prolinol derivatives, Cinchone‐derived primary amines and quaternary ammonium salts, and BINOL‐derived phosphoric acids account for the success of those methodologies. Moreover, the use of N‐sulfinyl imines with a dual role, as nitrogen nucleophiles and as chiral auxiliaries, appeared as a versatile mode of performing the asymmetric IMAMR. [ABSTRACT FROM AUTHOR]

The organocatalytic enantioselective desymmetrization reaction by means of an intramolecular (hetero)Michael addition is a useful strategy for the creation of complex carbo- and heterocycles with the generation of multiple stereocenters in a very simple manner. The intramolecular addition of carbon, oxygen and nitrogen nucleophiles to prochiral substrates bearing electronically deficient olefins takes place in the presence of organocatalysts, such as chiral primary and secondary amines, NHCs, ureas, thioureas, and BINOL phosphoric acid derivatives, reaching high levels of diastereo- and enantioselectivity. The main bottleneck of this methodology is the design and synthesis of the starting materials, which compromises its application. To date, the majority of examples are related to the use of 1,4-cyclohexanedione derivatives. [ABSTRACT FROM AUTHOR]

The intramolecular 1,3-dipolar cycloaddition of ortho-substituted 1,1,1-trifluoromethylstyrene-derived nitrones is described. Tricyclic fused isoxazolidines were obtained as major or exclusive products, in contrast to the case for nonfluorinated substrates, which rendered the bridged derivatives. This change in the regioselectivity was attributed to the electronic and, particularly, steric requirements of the trifluoromethyl group in comparison to the methyl group. It is worth mentioning that trifluoromethylstyrenes have been employed for the first time as dipolarophiles in a 1,3-dipolar intramolecular cycloaddition reaction, leading to the corresponding isoxazolidines bearing a quaternary trifluoromethyl moiety. Finally, the synthetic utility of the developed methodology has been illustrated with the synthesis of a family of bicyclic fluorinated 1,3-amino alcohols.