Betti's base for crystallization-induced deracemization of substituted aldehydes: synthesis of enantiopure amorolfine and fenpropimorph.

The acid-promoted crystallization-induced diastereoisomer transformation (CIDT) of naphthoxazines derived from racemic O-protected 2-substituted 4-hydroxybutyraldehydes and enantiopure Betti's base allows the deracemization of the starting aldehydes with ee up to 96%. As an alternative, reduction with lithium aluminum hydride of the diastereoisomerically enriched naphthoxazines leads to enantioenriched primary amines. The utility of the latter strategy was demonstrated by applying it to the synthesis of enantioenriched fenpropimorph and to the first synthesis of enantiopure amorolfine, with ee up to 99.5%.

Face and Mask: "Person" and "subjectivity" in Language and Through Signs.

In this paper, I will deal with the way linguistics and semiotics focus on person and subjectivity in language. I start from two different meanings of the "person" word and from Benveniste and Latour's theories of enunciation. Later, I deal with the problem of subjectivity in language and I connect it to two different views: Benveniste's idea that subjectivity is grounded on the "I" and Guillaume's idea of a primacy of the "he". Starting from the Iliad and from the semiotic idea of subject, I take side for Guillaume and Latour's theory: it is the delocutive structure of the "he" which, in language, expresses subjectivity, namely the capacity of the subject to make himself the object of his reflections and of his words.

A Two-Step Process for the Synthesis of Hydroxytyrosol.

A new process for the synthesis of hydroxytyrosol (3,4-dihydroxyphenylethanol), the most powerful natural antioxidant currently known, by means of a two-step approach is reported. Catechol is first reacted with 2,2-dimethoxyacetaldehyde in basic aqueous medium to produce the corresponding mandelic derivative with >90 % conversion of the limiting reactant and about 70 % selectivity to the desired para-hydroxyalkylated compound. Thereafter, the intermediate is hydrogenated to hydroxytyrosol by using a Pd/C catalyst, with total conversion of the mandelic derivative and 68 % selectivity. This two-step process is the first example of a synthetic pathway for hydroxytyrosol that does not involve the use of halogenated components or reduction methodologies that produce stoichiometric waste. It also avoids the complex procedure currently used for hydroxytyrosol purification when it is extracted from wastewater of olive oil production.

Stereoselective Michael addition of carbon-, nitrogen-, oxygen-, and sulfur-centered nucleophiles on enantiopure hydroxylated 6,7-dehydro-5-oxoindolizidine. Synthesis of carbon- or hetero-7-substituted swainsonine analogues.

Enantiopure alpha,beta-unsaturated delta-lactams 1 and 2 react stereoselectively with carbon-, nitrogen-, sulfur-, and oxygen-centered nucleophiles. The synthetic potential of these conjugate additions is demonstrated through the synthesis of two new substituted indolizidines: (7R)-7-amino-8-deoxyswainsonine 3 and (7R)-7-acetylaminoswainsonine 4.