Greater reactivity and higher selectivity of electrophilic reagents should obviate the need for Friedel-Crafts catalysts and permit control of the isomeric ratio of reaction products. A step in this direction is the use of compounds with “superleaving groups” such as CF₃SO or FSO.

The energetically favorable combination of two reactions—chloroolefin (or acetylene) + carbocation → adduct and adduct + acid → carboxylic acid, aldehyde or ketone—permits, e.g., the synthesis of adamantanechloroacetic acids and derivatives of β-amino acids such as (1).

“Oxo technology”—i.e. reactions of olefins with CO and H₂ to give aldehydes and their reaction products—profits from the use of Rh catalysts, which are 10³ to 10⁴-fold more effective than the conventional Co catalysts. Thus pressure and temperature can be varied more widely and the selectivity greatly enhanced, reaching 85% in the example shown.

The fight against pathogenic fungi is being fought with increasingly effective weapons. The optimization of the molecular shape of an active substance is presented for the title compounds as a cooperative venture of chemists and biologists.

Optically active epoxides such as (3) are useful components in the synthesis of complex chiral natural products. The simplest route to (S)-(3) probably leads from D-mannitol via diisopropylidenemannitol, (R)-(1), (S)-(2), and isomeric bromides obtained by ring opening.

A new entry to 1,2-oxazines of type (2) is provided by rearrangement of the oximes (1), which in turn arise from the corresponding ketones. R = (substituted) aryl.

New key compounds for facile syntheses of unsaturated carbo- and heterocycles are the chloroformamidinium chlorides (2). For example, (2) R = X = H, n = 1, reacts with NH₃ to give (3).

New difunctional synthetic building blocks of types (2) and (3) can be prepared by two methods. The reactants are (1) and N-tert-butyl-N-vinylcarbamoyl chloride. (3) exists in equilibrium with (2a), R¹ = R² = H, X = Cl.

Unchartered areas on the map of cycloadditions are becoming rarer and rarer. The hitherto neglected title reaction has now been studied with simple model systems; MO calculations are confirmed by the experimentally discovered formation of 3-substituted 1-pyrazolines (R = H, n-butyl, benzyl).

The smallest perfluorinated cyclic disulfone (1) has now been obtained by oxidation of the corresponding cyclic disulfide with CrO₃/HNO₃. (1) has unusually high symmetry.

Structural units of a tetrathiafulvalene and of a quinodimethane are present in the title compound (1), which is a potential donor component for CT complexes. Synthesis starts from the dibromide (2), which supplies the central component.

Reaction of thiophenolate with the carbyne complex (1) resembles neither that of phenolate nor that of selenophenolate [which yield PhCH₂—COOPh and (CO)₅Cr(PhSeSePh) and (CO)₄Cr(μ-SePh)₂Cr(CO)₄, respectively]. Instead, unexpected double addition gives the thiol ester (2).

Optimum conditions can now be predicted for the radical copolymerization of alkenes. It is only necessary to measure k_rel for addition of the cyclohexyl radical (by the “mercury method”) which is linearly related to the copolymerization parameters Q_j and e_j of the alkenes.

An aromatic vinylog of pyridine, aza[14]annulene (1), has been obtained in a multistep synthesis from the tetracyclic species (2), R = H. The conformationally mobile (1) exists in two inseparable forms in solution (ratio 4:1). As in the longer-known aza[18]annulene, the nitrogen occupies an internal position in the major component.

The four-membered ring in kinetically stabilized tetra-tert-butylcyclobutadiene has sides of almost equal length and is also folded. Perhaps even cyclobutadiene itself is “stabilized” by ring folding.—Derivatives previously studied have two long and two short sides.

Optically active amino acids not occurring in nature, are of interest, e.g. as potential enzyme inhibitors or as pharmaceuticals. Reaction of the lithiated lactim ether (1) obtainable from cyclo-(L-Ala-L-Ala) with carbonyl compounds and hydrolysis affords the α-methylserines (2) (and alanine).

The novel phosphorus “double ylides”, (3), Y = CH₂, (CH₂)₂, PPh, are potential chelating agents. Their formation can be interpreted as proceeding via the title compound (2), which is to be regarded as the lithium salt of a phosphorane anion on the basis of its reaction behavior.

The three stereoisomeric triepoxycycloheptanones (1), which could be transformed, inter alia, into trioxonines and into potentially “tris-homobenzenoid” carbenium ions, have been synthesized separately: the two “symmetrical” isomers from readily accessible (2), and the unsymmetrical isomer from (3).

“Electron-rich” butadienes (2) can be generated by deprotonation of 1-methyl-vinamidinium salts (1) with NaH and trapped as cycloadducts, e.g. (3).

Facile syntheses of numerous substituted pyridines and pyrimidines are permitted by cycloadditions to the diaminoazabutadienes generated from azavinamidinium salts. It has not yet been possible to isolate (1).

Combination of chiral aldehyde (1) and chiral reagent (2) (derived from 2-exo-3-exo-dihydroxy-3-endo-phenylbornane) permitted a diastereoselectivity of ca. 11:1 in the formation of alcohols (3) and (4). Cram preference and chiral control by the reagent reinforce each other.

The first dinuclear μ-nitrido complex of tungsten is the title compound, which arises in a slow side reaction during the preparation of AsPh₄[WNCl₄].

The first reaction of a heteroallene with a triorganotin anion has been accomplished with Ph₃SnLi and CS₂. The adduct could be trapped with MeI or EtI.

Only the ligand and not the metal participates in light-induced oxidation of the uncharged diamagnetic complexes (1) to the cations (2). The oxidation state of the metal (M = Ni^II, Pt^II) does not change. Such systems are of interest, e.g. as models for biochemical redox reactions.

Depending upon the oxidizing agent employed, various products are obtained from isatins (1): H₂O₂/glacial acetic acid leads to isatoic anhydrides (2), whereas H₂S₂O₈/H₂SO₄ furnishes 2,3-dioxo-1,4-benzoxazines (3). Compound (1) is usually oxidized to (2) with the toxic chromium trioxide.

A chromium complex with a carbene-analogous cumulene ligand has been isolated and characterized: (1), stable for some time at room temperature, was obtained from the propiolic acid derivative AgCCCO₂Na.

The first compound to contain the SO ligand, the cluster (1), can be regarded as an intermediate of reduction of sulfite to sulfide by iron carbonyl hydrides. The Fe₃SO grouping is of interest as a model for chemisorption of SO₂ onto metals.