Lorenzo Mangoni

Direct conversion of oxiranes to alkenes by chlorotrimethylsilane and sodium iodide

Abstract Smooth and quantitative conversion of oxiranes to alkenes is achieved by treatment with in situ generated iodotrimethylsilane.

Absolute configuration of homoisoflavanones from muscari species

Abstract The absolute configuration of homoisoflavanones isolated from Muscari species was determined by applying the chiral exciton coupling method to suitable derivatives. A negative Cotton effect in the 287–295 nm region of the CD curves of the natural compounds was shown to be indicative of 3R-configuration.

Cytotoxic 9,10-dihydrophenanthrenes from Juncus effusus L.

Abstract Nine 9,10-dihydrophenanthrenes, seven of them described for the first time, have been isolated in a further investigation of Juncus effusus. The structures have been defined on the basis of the spectral properties of the compounds. All the dehydrophenanthrene metabolites present in the plant have been tested for their cytotoxic properties and many of them have been found to have a good in vitro activity.

Three 3-benzyl-4-chromanones from Muscari comosum

Abstract Three novel 3-benzyl-4-chromanones have been isolated from the bulbs of Muscari comosum .

Activation of disarmed 2-O-alkoxycarbonylated glycosyl trichloroacetimidates with lanthanide triflates: an efficient approach for the synthesis of 1,2-trans glycosides

Disarmed glycosyl trichloroacetimidates can be activated by Yb(OTf)3 in the synthesis of 1,2-trans glycosides involving primary and secondary acceptors. Concurrent formation of orthoester side products can be avoided by the use of alkoxycarbonyl groups for the protection of the donor 2-hydroxyl.

Ten homoisoflavanones from two Muscari species

Abstract From the bulbs of Muscari armeniacum and of M. botryoides 10 novel homoisoflavanones were isolated. All these new 3-benzyl-4-chromanones were substituted with hydroxy or methoxy groups in the 3′- and 4′-positions.

Diterpenes from Araucaria bidwilli

Abstract Eight diterpent acids of the labdane or clerodane type were obtained from the oleoresin of Araucaria bidwilli and characterized as their methyl esters.

New diterpenes from Araucaria cunninghami

Abstract Eleven labdane diterpenes, nine of which are new compounds, were identified in the oleoresin of Araucaria cunninghami .

The relative and absolute configurations of stereocenters in caryophyllose

Abstract The complete stereochemistry of the monosacccharide 3,6,10-trideoxy-4-C-[(R)-1-hydroxyethyl]- d -erythro- d -gulo-decose, named caryophyllose, obtained from the lipopolysaccharide fraction of Pseudomonas caryophylli is reported. The relative stereochemistry was inferred by 1H NMR analysis and the absolute configuration was independently elucidated by Moshers and Exciton Chiral Coupling methods.

(20S)-4α-methyl-24-methylenecholest-7-en-3β-ol, an allelopathic sterol from Typha latifolia

Abstract An antialgal sterol with an unusual (20 S )configuration has been isolated from Typha latifolia . The structure, (20 S )-4α-methyl-24-methylenecholest-7-en-3β-ol (20- epi -24-methylenelophenol), has been defined by spectroscopic studies and chemical correlation.