Emanuela Marotta

Practical preparation of bicyclo[3.2.0]hept-3-en-6-ones and its utilisation in stereoselective total synthesis of grandisol and lineatin via a versatile intermediate

Abstract New and efficient stereoselective total syntheses have been devised for racemic grandisol and lineatin, two important components of pheromonic blends. They are based on the utilisation of 1,4-dimethylbicyclo[3.2.0]hept-3-en-6-one as a pivotal intermediate. This compound, as well as other bicyclo[3.2.0]hept-3-en-6-ones, are now easily available by a practical bicyclization of the corresponding 3-hydroxy-6-alkenoic acids.

Functionalized Nitroalkanes in Synthesis of 1,6-Dioxaspiro[4.5]decane Components of Paravespula vulgaris Pheromone

Abstract (E)-2-,(Z)-2-, and (E)-7-Methyl-1,6-dioxa[4.5]decane isomers which are components of odours of Paravespula vulgaris have been prepared by two practical and efficient procedures starting from easily available functionalized nitroalkanes.

Resolution and EPC synthesis of both enantiomers of 2,5-Dimethylbicyclo[3.2.0]heptan-endo-2-ol, Key Intermediate in the Synthesis of Grandisol.

Abstract The pure enantiomers of 2,5-dimethylbicyclo[3.2.0]heptan- endo -2-ol, key intermediate in the synthesis of grandisol, have been conveniently prepared by optiucal resolution with (2S)-(-)- and (2R)-(+)-1-(4-toluenesulphonyl)pyroolidine-2-carboxylic acid chloride (NTP-Cl) as resolving agents, and by an EPC synthesis employing commercially available (3R)-(-)-and (3S)-(+)-linalool as chiral sources.

(Z)-7-Nitro-3-Heptene as Central Intermediate for the Synthesis of Jasmone, Methyl Jasmonate, and γ Jasmolactone

Abstract (Z)-7-Nitro-3-heptene is used as central intermediate in the synthesis of jasmone (13), methyl jasmonate (15), and γ-jasmolactone (16), three jasmin constituents. Conjugate addition of the title nitro compound, by heterogeneous catalysis, to methyl vinyl ketone, or acrolein, or methyl acrylate, followed by Nef reaction, affords (Z)-undec-8-ene-2,5-dione, (Z)-1,4-dioxodec-7-ene, and (Z)-4-oxo-dec-7-enoic acid methyl ester respectively, which are easily converted into jasmone, methyl jasmonate and γ -jasmolactone.

Linear Aminopolyhydroxylated Structures Through Rapid Domino Assembly of a Highly Functionalized Heterotricyclic System and Its Selective Cleavage

Good selectivity and efficiency is achieved for the formation of heavily functionalized tricyclic systems, obtained in one or two steps from linear, readily available starting materials. The many functionalities assembled on the pivotal tricycle allow different procedures for unfolding it into interesting aminopolyhydroxylated structures in one or two steps (see scheme).

Consecutive and domino processes for the synthesis of a heavily functionalised tricyclic system

Abstract One pot multi-bond forming reactions are one of the ways to address the ever growing demand for efficiency in organic synthesis that concern the chemical community. This paper presents a new three-component domino process that efficiently combines four bond-forming reaction steps into a single synthetic operation. From easily available linear starting materials and under very mild conditions, this process builds five new bonds and four new chiral centers, giving rise to the selective formation of a new class of fused heteroatomic tricyclic system, which may be exploited for the synthesis of biologically interesting aminopolyhydroxylated compounds.

Synthesis of methyl substituted bicyclo[3.2.0]hept-3-en-6-ones and 3,3a,4,6a-tetrahydro-2H-cyclopenta[b]furan-2-ones.

Abstract Treatment of methyl mono- or bisubstituted 3-hydroxy-6-alkenoic acids in acetic anhydride and potassium acetate give the corresponding bicyclo[3.2.0]hept-3-en-6-ones in fair to good yields. This reaction appears to be of general applicability to prapare the methyl derivatives in all the portions of the five membered ring. The synthesis of 4,7,7-trimethylbicyclo[3.2.0]hept-3-en-6-one (filifolone) by an efficient bicyclization of 3-hydroxy-3-methyl-6-heptenoic acid followed by the geminal dimethylation of the intermediate 4-methylbicyclo[3.2.0lhept-3-en-6-one is reported. The latter reaction proved to be a general method when performed on bicyclo[3.2.0]hept-3-en-6-ones and on bicyclo[3.2.0]hept-2-en-6-one. 3,3a,4,6a-Tetrahydro-2H-cyclopenta[b]furan-2-ones, important starting materials in the synthesis of linear condensed triquinane sesquiterpenes, have been prepared in an efficient manner by the easy bicyclization of 3-hydroxy-6-heptenoic acids, followed by a Baeyer-Villiger oxidation of the bicyclo[3.2.0]hept-3-en-6-one intermediates.

Microbial and enzymatic approaches to chiral β- and γ-nitro alcohols

Abstract Microbial reductions of β- and γ-nitroketones 1–3 with various yeast and mould species and strains is described. Enzyme mediated resolutions of the racemic β- and γ-nitro alcohols 4–6 and of their O-acetyl derivatives 4a–6a are also reported.

Furan Ring as Masked 3‐Acylacrylate Moiety. Practical Synthesis of Racemic (E)4,4(Ethylenedioxy)‐7‐hydroxy‐2‐octenoic Acid, the C‐8 Subunit of Pyrenophorin.

Abstract Furfural and acetone are the starting materials for a new practical synthesis of racemic (E)4,4(ethylenedioxy)-7-hydroxy-2-octenoic acid, the protected C-8 subunit of Pyrenophorin. Furan ring has been used as masked 3-acylacrylate moiety.

Stereoselective total synthesis of racemic grandisol via 3-oximino-1,4,4-trimethylbicyclo[3.2.0]heptane. An improved practical procedure

Abstract (±)Grandisol was stereoselectively obtained via 1,4,4-trimethylbicyclo¦3.2.0¦heptane-3-one and its oxime by an improved procedure. 2,5,5-Trimethylhept-1,6-dien-4-ol, the open chain molecule, was synthesized by two routes. Its conversion into ( )grandisol was performed emploing the photobicyclization as key step.