2,3-Epoxyamide-alcohols in Domino Reactions: En Route to Molecular Diversity.

The synthesis of polycyclic γ- and δ-lactams bearing up to four contiguous fully controlled stereocenters is presented. For that purpose, we developed an original approach based on the use of 2,3-epoxyamides in domino reactions by taking advantage of the nucleophilic nitrogen atom and electrophilic epoxide. In reaction with enol ethers bearing gem bis-electrophiles on the double bond as Michael acceptors, four different reaction pathways were observed.

Pyrrolo-imidazo[1,2-]pyridine Scaffolds through a Sequential Coupling of -Tosylhydrazones with Imidazopyridines and Reductive Cadogan Annulation, Synthetic Scope, and Application.

A new strategy for the construction of 3-phenyl-1-pyrrolo-imidazo[1,2-]pyridine backbone is described. The reaction starts from the coupling between -tosylhydrazones and 2-chloro-3-nitroimidazo[1,2-]pyridines leading to the formation of 3-nitro-2-(arylvinyl)imidazo[1,2-]pyridine derivatives. Optimization of Cadogan-reductive conditions allowed the conversion of the obtained nitro derivative to a new scaffold of the type 3-aryl-1-pyrrolo-imidazo[1,2-]pyridine.

α-Halogenoacetamides: versatile and efficient tools for the synthesis of complex aza-heterocycles.

This review provides an overview of the applications of α-halogenoacetamides in domino and cycloaddition reactions. α-Halogenoacetamides are versatile building blocks that can lead to a wide variety of complex aza-heterocycles of biological interest when engaged in domino and/or cycloaddition reactions. The reactivity and the reaction conditions involved for these species (solvent, base, etc.

Chemo-, Regio-, and Stereoselective Synthesis of Polysusbtituted Oxazolo[3,2-d][1,4]oxazepin-5(3H)ones via a Domino oxa-Michael/aza-Michael/Williamson Cycloetherification Sequence.

The access to new oxazolo[3,2-d][1,4]oxazepin-5(3H)-ones starting from α-bromoamido alcohols and Michael acceptors under mild conditions is presented. This domino process proved to be chemo-, regio-, and stereoselective and allows the formation of a large diversity of highly functional 7-membered rings in good yields up to 95%. The complete shift of the regioselectivity of the intermediate enolate from a C-C to a C-O bond formation, contrary to the already known alkylations of such ambident nucleophiles, is mostly triggered by steric effects.

Synthetic Modification of 9α- and 9β-Hydroxyparthenolide by Heck or Acylation Reactions and Evaluation of Cytotoxic Activities.

Motivated by the widely reported anticancer activity of parthenolides and their derivatives, a series of new substituted parthenolides was efficiently synthesized. Structural modifications were performed at the C-9 and C-13 positions of 9- and 9-hydroxyparthenolide, which were isolated from the aerial parts of . Twenty-one derivatives were synthesized and evaluated for their cytotoxic activity against HS-683, SK-MEL-28, A549, and MCF-7 human cancer cell lines using the MTT colorimetric assay.

Synthesis of Oxazolidin-4-ones: Domino O-Alkylation/Aza-Michael/Intramolecular Retro-Claisen Condensation.

An original and rapid domino reaction for access to oxazolidin-4-ones is presented. Simply by heating α-bromoamido alcohol in the presence of KNaCO3 and water with readily prepared Michael acceptors, an unprecedented molecular rearrangement is generated. This new methodology enables the hitherto unreported synthesis of functionalized oxazolidin-4-ones.

Enolizable Carbonyls and N,O-Acetals: A Rational Approach for Room-Temperature Lewis Superacid-Catalyzed Direct α-Amidoalkylation of Ketones and Aldehydes.

An efficient catalytic room-temperature direct α-amidoalkylation of carbonyl donors, that is, ketones and aldehydes with unbiased N,O-acetals, is described. Sn(NTf2 )4 is an optimal catalyst to promote this challenging transformation at low loading and the reaction shows promising scope. A comprehensive and rational evaluation of this reaction has led to the establishment of an empirical scale of nucleophilic reactivity for a broad set of ketones that should be helpful in the synthetic design and development of carbonyl α-functionalization methods.

Sequential Friedel-Crafts-Type α-Amidoalkylation/Intramolecular Hydroarylation: Distinct Advantage of Combined Tf2NH/Cationic LAu(I) as a Consecutive or Binary Bicatalytic System.

The combined use of Tf2NH and L(Au)(+)X(-) as a dual or binary catalytic system clearly improves the efficiency and enlarges the scope of the tandem intermolecular Friedel-Crafts α-amidoalkylation/intramolecular hydroarylation sequence, compared to an "all gold" multicatalysis approach.

Synthesis and biological evaluation of 9α- and 9β-hydroxyamino-parthenolides as novel anticancer agents.

A series of 9α-hydroxyamino-parthenolides 3-10, 9β-hydroxyamino-parthenolides 11-13 and 9α-hydroxy-1β,10α-epoxyamino-parthenolides 15-19 were efficiently synthesized starting from 9α-hydroxyparthenolide 1 and 9β-hydroxyparthenolide 2, which were isolated from Anvillea radiata. Compounds 1-13 and 15-19 were evaluated for their in vitro anticancer activity by the MTT colorimetric assay against one murine and six human cancer cell lines. This work provides new details about the structural requisites for anticancer activity.