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1,3-Dipolar cycloadditions of nitrones with pentafluorosulfanyl-substituted acrylic ester and amides afforded new trisubstituted pentafluorosulfanylated isoxazolidines in moderate yields as 4-SF5-regioisomers. Theoretical calculations were carried out and the regioselectivity could be explained by the fact that the 5-SF5-regioisomer probably undertook a spontaneous degradation in the reaction medium via the loss of pentafluorosulfanyl anion. Diastereoselectivity of the 1,3-dipolar cycloadditions was also assessed according to NMR and X-ray diffraction analysis.

A new approach to enantiopure disubstituted oxaprolinol derivatives through diastereoselective [3+2]-cycloaddition of chiral cyclic ketonitrones to electron-rich and electron-poor dipolarophiles is presented.

The first example of a high facial selective [3 + 2] cycloaddition employing chiral vinyl ethers as dipolarophile and nitrones as dipoles is presented.

In the presence of the Ru catalyst (RUC), ketonitrones of type (I) are found to react with methacrolein with high regio-, diastereo-, and enantioselectivity.

A series of para-substituted benzhydrylamines 6 were obtained by substitution of the corresponding benzhydrol precursors 1 with phenyl carbamate 2 under acidic conditions, followed by basic hydrolysis of the carbamate intermediates 3. One unsymmetrical intermediate 3i has been resolved by preparative chiral chromatography. Subsequent deprotection of the carbamate function led to the recovery of enantiomerically pure (+)- and (-)-4-chlorobenzhydryl amines.

Amino acid derived nitrones were conveniently synthesized in good-to-excellent yields by condensation of α-ketoesters with N-benzylhydroxylamine. The cycloaddition reactions of these nitrones with different alkenes were investigated under thermal solvent-free conditions. Considering conversions, yields, and selectivities, alkyl vinyl ethers have proven to be valuable partners to achieve this transformation, which creates a tetrafunctionalized stereogenic quaternary center. From the adducts derived from vinyl ethers, a three-step access to highly functionalized α-substituted amino acid derivatives is described.

A mild and efficient procedure for the selective cleavage of N-benzhydryl protecting group of beta-lactams is described. The protected 2-azetidinones 4, precursors of carbapenems, were treated with a stoichiometric amount of N-bromosuccinimide and a catalytic amount of bromine under sun light irradiation in CH2Cl2-H2O mixture at 20 degreesC for 3 hours. The N-benzhydrol intermediates 6, which could be isolated, were then hydrolyzed with p-TsOH in aqueous acetone to furnish beta-lactams 7 and benzophenone quantitatively.