Introduction Cationic domino reactions Anionic domino reactions Radical domino reactions Pericyclic domino reactions Photochemically induced domino processes Transition metal catalysis Domino reactions initiated by oxidation or reduction Enzymes in domino reactions Multicomponent reactions Special techniques in domino reactions

Domino Reactions in Organic Synthesis

Schiff bases: A short review of their antimicrobial activities

Recent developments in the stereoselective synthesis of α-aminoacids

The Henry reaction: recent examples

The asymmetric organocatalysis is definitely one of the most powerful and versatile tools for the rapid construction of various spirocyclic oxindoles. In the past few years, a number of successful strategies based on organocatalysis have been developed for the construction of 3,3′-spirocyclic oxindoles in high yields and excellent enantioselectivities under mild conditions. In this review, recent advances in this area are summarized and classified according to the spiro ring fused at the 3-position of the oxindole core.

Recent Advances in Asymmetric Organocatalytic Construction of 3,3′-Spirocyclic Oxindoles

Synthesis of natural products via isoxazoles

The α-ketoamide motif is widely found in many natural products and drug candidates with relevant biological activities. Furthermore, α-ketoamides are attractive candidates to synthetic chemists due to the ability of the motif to access a wide range of functional group transformations, including multiple bond-forming processes. For these reasons, a vast array of synthetic procedures for the preparation of α-ketoamides have been developed over the past decades, and the search for expeditious and efficient protocols continues unabated. The aim of this review is to give an overview of the diverse methodologies that have emerged since the 1990s up to the present. The different synthetic routes have been grouped according to the way the α-ketoamide moiety has been created. Thus, syntheses of α-ketoamides proceeding via C(2)-oxidation of amide starting compounds are detailed, as are amidation approaches installing the α-ketoamide residue through C(1)-N bond formation. Also discussed are the methodologies centered on C(1)-C(2) σ-bond construction and C(2)-R/Ar bond-forming processes. Finally, the literature regarding the synthesis of α-ketoamide compounds by palladium-catalyzed double-carbonylative amination reactions is discussed.

Recent Developments in General Methodologies for the Synthesis of α-Ketoamides

Tetramethylguanidine (TMG)-catalyzed addition of dialkyl phosphites to α,β-unsaturated carbonyl compounds, alkenenitriles, aldehydes, ketones and imines

Natural and man-made organosulfur compounds play important roles in biological and medicinal chemistry. Among the various classes of organic sulfur compounds, dihydroand especially tetrahydrothiophenes have attracted particular attention because of the widespread occurrence as ring system motifs in natural and nonnatural products displaying a broad spectrum of biological activities. Tetrahydrothiophene-based compounds include the essential coenzyme biotin 1, a water-soluble vitamin involved in important biological functions, and the potent α-glucosidase inhibitors salacinol 2 6 and kotalanol 3, isolated from several Salacia plant species. Recently, the related compounds salaprinol 4 and ponkoranol 5 were isolated from Salacia prinoides, and significant efforts to prepare these cyclic sulfonium salts and synthetic analogues, including 6 and 7, have been made in the past few years (Figure 1). Further representative compounds are the 40-thioadenosine derivative 8, a highly potent and selective A3 adenosine receptor antagonist; the 40-thiocytidine nucleoside 9, active against HSV-1 and HSV-2; the cholecystokinin type-B receptor antagonist tetronothiodin 10; and (R)-tetrahydrothiophen-3-ol 11, 18 a pivotal intermediate to obtain the potent antibacterial Sulopenem 12 (Figure 2). The field of applications of tetrahydrothiophenes is impressively wide in scope: these compounds have been employed as templates to assist and control various chemical transformations, including asymmetric hydrogenation, catalytic asymmetric epoxidation, and catalytic intramolecular cyclopropanation. Moreover, adsorption of tetrahydrothiophene on gold has emerged as a powerful tool to obtain self-assembled monolayers (SAMs), which can be used to control physical and chemical properties of surfaces for various technological purposes. The dihydrothiophene ring system is a common structural feature of many bioactive compounds, some of which are shown in Figure 3. In particular, (S)-ethyl 4-amino-4,5-dihydrothiophene-2-carboxylate 13 inhibits copper amine oxidases (CAOs), the unnatural L-nucleoside 14 displays potent anti-HIV activity without significant toxicity, and 4,5-dihydrothiophene-3-carbonitrile 15 exhibits antibacterial and antifungal properties. Interestingly, it has been demonstrated that calicheamicin becomes active Figure 1.

Gian Piero Pollini

Papers

Synthesis of natural products via isoxazoles

Recent Developments in General Methodologies for the Synthesis of α-Ketoamides

Tetramethylguanidine (TMG)-catalyzed addition of dialkyl phosphites to α,β-unsaturated carbonyl compounds, alkenenitriles, aldehydes, ketones and imines

Synthetic Routes to Chiral Nonracemic and Racemic Dihydro- And Tetrahydrothiophenes

Synthetic approaches to enantiomerically pure 8-azabicyclo[3.2.1]octane derivatives.