Gianni Porzi

A facile synthesis of symmetrical secondary amines from primary amines promoted by the homogeneous catalyst RuCl2(Ph3P)3

Abstract Primary amines bearing an α-hydrogen atom are quantitatively converted to symmetrical secondary amines by heating at 185°C for 5 h in the presence of a catalytic amount of RuCl 2 (Ph 3 ) 3 .

Selective conversion of primary amines into N,N-dimethylalkyl- or N,N-dialkylmethyl-amines with methanol and RuCl2(Ph3P)3

N,N-dimethylalkyl- or N,N-dialkylmethyl-amines are selectively obtained from the reaction between aliphatic amines and methanol at 180°C for 7 h in the presence of RuCl2(Ph3P)3 catalyst.

A new synthesis of both the enantiomers of 4-amino-3-hydroxybutanoic acid (gabob) and mm2 calculations for rotamers of the intermediate oxazolidin-2-on

Abstract The easy Chromatographic separation of the diastereomertic mixture of oxazolidin-2-ones 4a and 4b allows to synthesize pure R-(-)- la and (S)-(+)-GABOB 1b . The 1H NMR pattern of 4a and 4b can be correlated with the configuration at C-5 and this relationship is confirmed by MM2 calculations for rotamera of 5-substituted oxazolidin-2-ones.

A simple asymmetric synthesis of (+)- and (−)-2,6-diaminopimelic acids

Abstract The asymmetric synthesis of both the enantiomers of 2,6-diaminopimelic acid (2,6-DAP) has been accomplished starting from the chiral synthon 1.

Synthesis of (3R,6R)- and (3S,6S)-3,6-dialkylpiperazin-2,5-dione derivatives as useful intermediates to both (R) and (S) α-aminoacids

Abstract The alkylation of 2 leads to a diastereomeric mixture where 4 is generally present in greater amounts than 3 . The successive alkylation of 4 affords exclusively the cis derivative 7 , while a cis/trans mixture is obtained from isomer 3 . In alkaline solution, the trans isomer 6 suffers a total conversion into a 1:1 mixture of the cis isomers 5 and 7 easily separated by silica gel chromatography. The configurations of the introduced stereogenic centers at C-3 and C-6 have been assigned on the basis of 1 H-NMR spectroscopic data. Cleavage of heterocyclic ring of 5 and 7 leads to the corresponding ( R )- and ( S )-α-aminoacidsrespectively. Therefore, the substrate 2 appears a very useful chiral template to synthetize enantiomerically pure α-amino acids.

A new approach to 2-phenylthioalcohols in high optical purity

Abstract 2-Phenylthioalcohols are prepared in high optical purity by alkylation of chiral imides of 2-phenylthioacetic acid, obtained starting from chiral imidazolidin-2-ones.

Unusual peptides containing the 2,6-diaminopimelic acid framework: Stereocontrolled synthesis, X-ray analysis, and computational modelling. Part 2

Abstract The stereocontrolled synthesis of peptides 6, 9 and 14, structural variants of 2,6-diaminopimelic acid, was carried out starting from the chiral synthon 1, easily obtained from l -valine. The configuration of the introduced stereogenic centres has been assigned on the basis of 1H NMR spectroscopic data. X-Ray crystal structure and conformation analysis of 5 are also reported.

Stereoselective synthesis of α,α′-diamino-dicarboxylic acids. Part 2☆

Abstract Enantiomerically pure α,α′-diamino-dicarboxylic acids ( R , R )- 4 , ( S , S )- 5 and ( S , S )- 7 have been synthesized starting from the glycine-derived chiral synthon ( S , S )- 1 .

The homogeneously catalysed synthesis of N-methyldi-alkylamines from n-methyl and N,N-dimethylalkylamines

Abstract N-Methyl and N,N-dimethylalkylamines are converted into N-methyldialkyl-amines in good yields when heated at 180°C in the presence of a catalytic amount of RuCl 2 (Ph 3 P) 3- .

A new stereocontrolled synthesis of uncommon tripeptides derived from 2,6-diaminopimelic acid (2,6-DAP)

Abstract The stereocontrolled synthesis of uncommon tripeptides 8 and 11a – c , structural variants of 2,6-diaminopimelic acid, was carried out starting from the mono-lactim ether 1 easily obtained from l -valine. The configurations of the introduced stereogenic centers were assigned on the basis of 1 H NMR spectroscopic data.