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The hitherto unknown stereochemistry concerning the formation of 2,3-disubstituted cycloheptanones by the Michael addition reaction was studied. The Michael addition of thiophenol to 3-substituted 2-methylene-cycloheptanones in the presence of triethylamine in THF at ambient temperature produced 3-substituted 2-[(phenylthio)methyl]cycloheptanones with high cis selectivity (>96/4), which was unequivocally established by 1 H NMR and X-rays analyses

Reversal of enantioface selectivity was observed by merely switching the solvent from CH2Cl2 (enantiomer ratio of the adduct = 91:9) to THF (14:86) in the asymmetric Diels-Alder reaction catalyzed by the aluminum complex of a newly prepared chiral methol derivative. Negative nonlinear effect on the relationship between enantiomeric excesses of the reaction product and optical purities of the ligand was observed for the reaction in CH2Cl2 whilst linear relationship for that in THF.

Ab initio molecular orbital calculations at the MP4(SDTQ)/6-31G∗//RHF/6-31G∗ level of theory were used to obtain detailed insight into the reaction profile on the Mg controlled 1,3-cycloaddition of nitriles oxide with allylic alcohols. It was confirmed that the complex formation reduces the HOMO–LUMO energy gaps of the two reactants. The propensity correlates well to calculated activation energies of the cycloaddition. The syn-stereoselectivity depends on the steric repulsion between the vinyl fragment and the substituent at the α-position of the alcohol or alkoxide. THF or Et2O in the reaction mixture prevent the coordination of R1CNO from forming the Mg intermediate and result in deccelerating the cycloaddition. The results obtained in the present study well explain an important role of the Mg2+ ion in the 1,3-dipolar cycloadditions of nitrile oxides with allylic alcohols.

In the presence of magnesium perchlorate, 1,3-dipolar cycloaddition reactions of nitrile oxides to crotonamide bearing 4-benzyl-5,5-dimethyl-1,3-oxazolidin-2-one as the chiral auxiliary proceeded with a regio- and diastereo-selective manner to afford the corresponding chiral 2-isoxazoline. The mechanisms underlying the diastereoface selection in the cycloaddition reaction were investigated using the B3LYP/6-31G* level of theory.

The reaction of nitro olefins with thiolate anions followed by protonation at −78 o C gives anti-β-nitro sulfides. This procedure can be applied to the anti-selective preparation of β-nitro ethers and β-nitro selenides. The reaction of cyclic nitro olefins with aryl thiol gives cis-β-nitro sulfide in excellent selectivity. The conjugate addition of alkylaluminum reagents to phenylthio β-nitro olefins followed by protonation at −78 o C also results in selective formation of anti-β-nitro sulfides. Theoretical calculations show that the methylthio group on the β-position covers the one side of the nitronate plane effectively to give the anti isomer in a stereoselective way

The vinyl cation with a ethynyl fragment, C4H3+ is investigated with ab initio molecular orbital calculations. Two geometrical isomers of C4H3+, open chain and triangular geometries are calculated in order to ascertain the existence of the triangular isomer. The 4–31G* and MP3/6–31G*//4–31G* level calculations confirm that the latter is more stable than the former. However, the activation energy for intra-conversion is considered to be rather small. The calculated results are analyzed by comparing with experimental results. The relation between molecular vibration and reaction is analyzed by dynamic electron transfer.