Aliphatic aldehydes were reacted with nitro alkanes in the presence of catalytic amounts of piperidine over 4 A molecular sieves. Simply by changing reaction conditions (solvent and temperature) it is possible to control the stereochemical outcome of the reactions, obtaining pure (E)- and (Z)-nitro alkenes in high to excellent yields. The role of molecular sieves on the stereochemical control seems crucial in addition to that of piperidine, especially for the synthesis of the Z isomer.

The bisaziridination reaction of symmetric (E-s-trans-E)-α-diimines using ethyl nosyloxycarbamate as aminating agent yields symmetrically functionalized bidiaziridines, under mild conditions. The reactions take place with very high stereoselectivity giving only bidiaziridines with total retention of the starting α-diimine configuration, as determined by NMR measurements. Moreover, only a single pure diastereomer, derived from attack of the aza-anion on the opposite faces of conjugate system was obtained, starting from chiral substrates. ROESY analyses clearly show that all nitrogens have a stable pyramidal conformation, and the absolute configurations of new chiral centers were assigned.

We study by molecular dynamics simulations the hydration of beta-cyclodextrin. Our simulations show that within these barrel-shaped molecules hydrophobicity dominates, while at the top and bottom sides of the barrel interactions with water are mostly hydrophilic in nature. These results agree with crystallographic data at 120 K and, in particular, with the spontaneous hydration process of a cyclodextrin crystal in wet atmosphere. The predicted structure of the hydration shells is discussed and compared with previous molecular mechanics calculations which report an overall hydrophobic behavior. Moreover, the temperature dependence of the hydration process is discussed.

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[reaction: see text] The amination of 2-(trifluoromethyl)acrylates, performed by nosyloxycarbamates, gives two different aminated products, the derivatives of alpha-trifluoromethyl beta-amino esters or the aziridines, in high yields by changing the reaction conditions. The aza-Michael addition product was isolated for the first time in this kind of reaction. This finding confirms the aza-MIRC mechanism we previously proposed. Asymmetric induction was also pursued.

Efficient one-pot methods for the synthesis of variously functionalised conjugated nitro alkenes have been reported. Despite the utility in different fields of these compounds, only a few multi-step syntheses have been reported in the literature, giving the target compounds in low overall yields. α-Nitro acrylates or cinnamates, α-nitro α,β-unsaturated ketones and, most importantly, aromatic and heteroaromatic (E)- 2-nitro allylic alcohols, compounds characterised by a well-known anticancer activity, were obtained in high yields and high diastereomeric purity by a domino condensation-dehydration process.

ZrCl(4) was found to be an ideal catalyst to promote aza-Henry reactions between trifluoromethyl aldimines and some nitro alkanes giving new fluorinated β-nitro amines. The reaction is strongly influenced by the CF(3) group, the yield by the alkyl chain of the nitro compound, while the stereochemical outcome seems to be unaffected, the anti isomer being always the major product.

Aza-MIRC (Michael-initiated ring closure) and C-H insertion products were obtained in the reactions of trifluoromethylated olefins with different nosyloxycarbamates by changing base and solvent. Aza-Michael addition products were not isolated. The presence and the position of the trifluoromethyl group allow control of the outcome of the reactions.