Effect of Chain Length on Radical to Carbanion Cyclo-Coupling of Bromoaryl Alkyl-Linked Oxazolines: 1,3-Areneotropic Migration of Oxazolines

Reaction of Diisobutylaluminum Borohydride, a Binary Hydride, with Selected Organic Compounds Containing Representative Functional Groups

The binary hydride, diisobutylaluminum borohydride [(iBu)₂AlBH₄], synthesized from diisobutylaluminum hydride (DIBAL) and borane dimethyl sulfide (BMS) has shown great potential in reducing a variety of organic functional groups. This unique binary hydride, (iBu)₂AlBH₄, is readily synthesized, versatile, and simple to use. Aldehydes, ketones, esters, and epoxides are reduced very fast to the corresponding alcohols in essentially quantitative yields. This binary hydride can reduce tertiary amides rapidly to the corresponding amines at 25 °C in an efficient manner. Furthermore, nitriles are converted into the corresponding amines in essentially quantitative yields. These reactions occur under ambient conditions and are completed in an hour or less. The reduction products are isolated through a simple acid-base extraction and without the use of column chromatography. Further investigation showed that (iBu)₂AlBH₄ has the potential to be a selective hydride donor as shown through a series of competitive reactions. Similarities and differences between (iBu)₂AlBH₄, DIBAL, and BMS are discussed.

Iterative double cyclization reaction by SRN1 mechanism. A theoretical interpretation of the regiochemical outcome of diazaheterocycles

Diazaheterocyclic compounds are prepared in good yields by double cyclization intramolecular S_RN1 reactions from diamines bearing two aryl iodide moieties.

Preparation of SRN1-Type Coupling Adducts from Aliphatic gem-Dinitro Compounds in Ionic Liquids

S_RN1-type coupling adducts are readily prepared by the reaction between α-sulfonylesters or α-cyanosulfones and gem-dinitro compounds in ionic liquids. The reactions progress smoothly and recovered ionic liquids can be used for several iterations, as long as they are washed with water to remove alkali metallic salts. The reaction rate is slower than the corresponding S_RN1 reaction in DMSO, but no acceleration on irradiation or no inhibition in the presence of m-DNB are observed.

Theoretical investigation on carbon-centered tri-s-tetrazine and its 10 derivatives

A novel species, carbon-centered tri-s-tetrazine (C(4)N(9)H(3)), and its 10 derivatives (C(4)N(9)R(3), where R=OH, F, CN, N(3), NH(2), NO(2), N=NH, N(2)H(3), C triple bond CH, and CH=CH(2)) have been studied computationally. Density functional theory (DFT) has been used to study the geometries, electronic structure, harmonic vibrational frequencies, ionization energies of the 11 compounds at the restricted (for neutrals) and the unrestricted (for cations) B3LYP/cc-pVDZ level of theory. Atoms in molecule (AIM) and natural bond orbital (NBO) analyses have been used to obtain the bonding properties. Valence bond (VB) theory is applied to explain the unusual pyramidal structure around the carbon-center and electron arrangements of orbitals. We found: (1) All the species possess novel bonding features and geometrical structures. The atoms on the periphery of each species are sp(2) hybridized. Each of these atoms offers an orbital to form an extensive conjugation system (12)pi(15) (a pi system consisting of 12 centers and 15 electrons). The central carbon atom C13 is sp(3) hybridized, which makes the non-planar molecule shape like a straw-hat. Atom C13 also participates in the conjugated pi system with its sp(3) hybridized orbital, thus forming an extensive (13)pi(16) conjugate pi system covering the whole C(4)N(9) framework. (2) The change of charge on C13 is the largest among all the atoms when the species is ionized and the atomic charges are redistributed. In other words, C13 is the attack center for electrophilic agents. Thus, the species is carbanion-like. (3) All the species have low ionization energies (IEs). The electron ionized mainly comes from C13. They may have wide applications in organic chemistry, in organometallic chemistry and in alkyl lithium chemistry once they are synthesized.