Valeria Di Bussolo

Acetamidoglycosylation with Glycal Donors: A One‐Pot Glycosidic Coupling with Direct Installation of the Natural C(2)‐N‐Acetylamino Functionality

Nitrogen transfer to glycals: A new method for direct C2-aza-glycosylation with glycal donors has been developed (see scheme), employing the new reagent combination of thianthrene-S-oxide and trifluoroacetic anhydride for glycal activation, in an overall one-pot procedure.

Regio- and Stereoselective Ring Opening of Enantiomerically Enriched 2-Aryl Oxetanes and 2-Aryl Azetidines with Aryl Borates

The regioselective ring opening of 2-aryl-substituted four-membered heterocyclic rings with phenols, including catechol, was achieved by the use of aryl borates in mild and neutral reaction conditions without the aid of any transition metal catalysts. While N-alkyl azetidines were found not to be reactive, optically active N-tosyl azetidines gave the corresponding beta-aryloxy amines in a racemic form, thus indicating the considerable carbocationic character of the transition state. The introduction of a hydroxyl group in the azetidine ring (i.e., an azetidinol), able to anchor the aryl borate and to direct the subsequent nucleophilic delivery, was shown to determine the ring-opening process with predominant inversion of configuration. When enantiomerically enriched 2-aryl oxetanes were used, the reduced extent of racemization observed (up to 93:7 er) was rationalized by an intramolecular delivery through a six-membered transition state, giving beta-aryloxy alcohols with a predominant retention of configuration (i.e., a syn-stereoselective ring opening). The aryloxy alcohols obtained, endowed with suitable functionalities, can be cyclized to give access to enantiomerically enriched 2-aryl-1,5-benzodioxepins.

Synthesis and antiviral properties of 9-[(2-methyleneaminoxyethoxy)methyl]guanine derivatives as novel Acyclovir analogues.

This paper reports the synthesis and the antiviral properties of a series of 9-[(2-methyleneaminoxyethoxy)methyl]guanine derivatives, which can be viewed as analogues of the antiherpes drug Acyclovir (ACV) from which they differ in the replacement of its hydroxy group with variously substituted methyleneaminoxy moieties. Some of the newly synthesized compounds proved to possess a certain activity against HSV-1, albeit lower than that of ACV.

Dual Targeting of the Warburg Effect with a Glucose‐Conjugated Lactate Dehydrogenase Inhibitor

Effective glucose diet: We report the development and activity of glucose-conjugated LDH-A inhibitors designed for dual targeting of the Warburg effect (elevated glucose uptake and glycolysis) in cancer cells. Glycoconjugation could be applied to inhibitors of many enzymes involved in glycolysis or tumor metabolism.

Synthesis and Ring-Opening Reactions of the Diastereoisomericcis- andtrans-Epoxides Derived from 3-(Benzyloxy)cyclopentene and 2-(Benzyloxy)-2,5-dihydrofuran

The regiochemical outcome of the ring-opening of epoxides bearing remote polar functionalities has been established in the case of carbocyclic (1 and 2) and the corresponding furanosidic (3 and 4) title epoxides. Under standard conditions, the regioisomeric C-1 products are the sole (from trans epoxides 2 and 4) or predominant (from cis epoxides 1 and 3) ring-opening products. However, under chelating conditions, and only in the case of the cis epoxides 1 and 3, a consistent increase in C-2 selectivity is unexpectedly observed.

Yttrium triflate-catalyzed addition of lithium enolates to 1,2-epoxides. Efficient synthesis of γ-hydroxy ketones

A simple, efficient method is described for the synthesis of γ-hydroxy ketones by the direct opening of 1,2-epoxides with lithium enolates derived from simple ketones in anhydrous toluene, in the presence of Y(OTf)3.

REGIO- AND STEREOSELECTIVITY IN THE CYCLIZATION OF ENOLATES DERIVED FROM 4,5-, 5,6-, AND 6,7-EPOXY-1-PHENYL-1-ALKANONES. COMPETITION BETWEEN C- AND O- ALKYLATION

Abstract The results obtained in the base-catalyzed intramolecular cyclization of enolates derived from some representative 4,5-, 5,6-, and 6,7-epoxy ketones and of the corresponding alkenes are discussed. The LHMDS/Sc(OTf)3 protocol on epoxy ketones appears to be a valuable tool for the stereoselective obtainment of the corresponding cyclic γ-hydroxy ketones (γ-HKs).

Regiochemical control of the ring opening of 1,2-epoxides by means of chelating processes. Part 17: Synthesis and opening reactions of cis- and trans-oxides derived from (2S,6R)-2-benzyloxy-6-methyl-3,6-dihydro-2H-pyran, (2R,6R)- and (2S,6R)-2-methoxy-6-methyl-5,6-dihydro-2H-pyran

Abstract The regiochemical behavior of the title deoxy anhydrosugars, prepared in an enantioselective way starting from methyl α- d -glucopyranoside, was examined in opening reactions, both under standard and chelating conditions. The results clearly indicate the influence of the reaction conditions and the importance of the relative orientation of the methyl group with respect to the oxirane ring on the regiochemical outcome of these epoxides. An useful inversion of regioselectivity is obtained in some cases.

Regiochemical Control of the Ring Opening of 1,2-Epoxides by Means of Chelating Processes. Part 14: Regioselectivity of the Opening Reactions with MeOH of Remote O-Substituted 1,2-Epoxycyclohexanes under Gas-Phase Operating Conditions.

Abstract The regiochemical behavior of cyclohexene oxides bearing a remote O -functionality was determined in the gas-phase in opening reactions with MeOH, using a gaseous acid (D 3 + , C n H 5 + , Me 2 F + ) as the promoting agent. The results obtained indicate the incursion in the opening process in the gas phase of H + (or D + )-mediated chelated bidentate species completely absent in the corresponding reactions (methanolysis) carried out in the condensed phase.

A novel effective transition metal based salt-catalyzed azidolysis of 1,2-epoxides

Abstract A simple, efficient, stereoselective, and in some cases usefully non-regioselective method for the synthesis of β-azido alcohols by the direct opening of 1,2-epoxides with 1,1,3,3-tetramethylguanidinium azide (TMGA) in CH3CN, catalyzed by simple transition metal-based salts [Hf(OTf)4, Zr(OTf)4, Yb(OTf)3], is described. Also TMSN3 may be used in some reactions as a source of N3−. This new method appears to be competitive with other methods previously reported.