Synthesis, Structure, and Transformation of Novel Osmium Azine and Ylide Complexes

One Reacts as Two: Applications of N-Isocyaniminotriphenylphosphorane in Diversity-Oriented Synthesis

N-Isocyaniminotriphenylphosphorane (NIITP) is a functionalized isonitrile that has been extensively applied in a variety of organic reactions during the last two decades. This Review summarizes the most important applications in organic synthesis of this versatile reactant, with the focus posed on mechanistic and methodological aspects allowing the generation of molecular diversity. NIITP combines the reactivity of isonitriles with that of phosphoranes to enable chemical transformations employed in the construction of compound libraries. Here, we cover from the initial applications of NIITP in the Nef isocyanide reaction to further derivations that render a variety of heterocyclic scaffolds. The presence of the isonitrile moiety in this singular compound makes possible the double addition of nucleophiles and electrophiles, which followed by inter(intra)molecular aza-Wittig type transformations enable several multicomponent and tandem processes. In particular, we stress the impact of NIITP in oxadiazole chemistry, from the early two-component transformations to recent examples of multicomponent reactions that take place in the presence of suitable electrophiles. In addition, we briefly describe the role of NIITP chemistry in generating skeletal and conformational diversity in cyclic peptides. The reaction of NIITP with alkynes is thoroughly revised, with particular emphasis on silver-catalyzed processes that have been developed in the last years. Biomedicinal applications of some reaction products are also mentioned along with a perspective of future applications of this reactant.

Geminal Dianions Stabilized by Main Group Elements

This review is dedicated to the chemistry of stable and isolable species that bear two lone pairs at the same C center, i.e., geminal dianions, stabilized by main group elements. Three cases can thus be considered: the geminal-dilithio derivative, for which the two substituents at C are neutral, the yldiide derivatives, for which one substituent is neutral while the other is charged, and finally the geminal bisylides, for which the two substituents are positively charged. In this review, the syntheses and electronic structures of the geminal dianions are presented, followed by the studies dedicated to their reactivity toward organic substrates and finally to their coordination chemistry and applications.

Experimental and theoretical study on diethyl-(Z)-2-(5,7-diphenyl-1,3,4-oxadiazepin-2-yl)-2-butenedioate using different levels of computational methods

In this research work, diethyl-(Z)-2-(5,7-diphenyl-1,3,4-oxadiazepin-2-yl)-2-butenedioate, 7, was synthesized and characterized by FT-IR, 1H NMR, 13C NMR spectroscopy, elemental analyses and mass spectra. The reliabilities of various ab initio methods including HF and B3LYP were evaluated. The bond lengths, bond angles, dihedral angles, charge density on atoms at 7 were calculated. The ab initio calculations indicated that the B3LYP method with a 6-311++G(d,p) basis set can give accurate results. The 13C NMR and 1H NMR chemical shifts of 7 calculated and compared with the related experimental data. The HOMO, LUMO, molecular electrostatic potential (MEP) of 7 were investigated. The thermodynamic parameters and physico-chemical properties were calculated.

Ultrasonics in isocyanide-based multicomponent reactions: a new, efficient and fast method for the synthesis of fully substituted 1,3,4-oxadiazole derivatives under ultrasound irradiation

A fast and convenient approach to the synthesis of fully substituted 1,3,4-oxadiazoles via three-component reaction of aromatic carboxylic acids, acenaphthoquinone, and (N-isocyanimino)triphenylphosphorane under ultrasound irradiation is described. Furthermore, a series of compounds were synthesized and characterized by melting point, IR, NMR and MS. Utilization of easy reaction conditions, very high to excellent yields, and short reaction times makes this manipulation potentially very useful.