Multicomponent one-pot

A family of interesting polycychc systems 106 related to pyrrolidines was obtained in a one-pot double intermolecular 1,3-dipolar cycloaddition, irradiating derivatives of o-allyl-sahcylaldehydes with microwaves in toluene for 10 min in presence of the TEA salt of glycine esters [71]. A very similar approach was previously proposed by Bashiardes and co-workers to obtain a one-pot multicomponent synthesis of benzopyrano-pyrrolidines 107 and pyrrole products 108 (Scheme 37). The latter cycloadducts were obtained when o-propargylic benzaldehydes were utihzed instead of o-allyhc benzalde-hydes, followed by in situ oxidation [72]. 

Ugi, I. K., New aspects of natural and preparative of one-pot multicomponent reactions and their libraries, in Ehefeld,... 

Lombardo, M. Trombini, C. (1998) One-Pot Multicomponent Reactions. In Seminars in Organic Synthesis XXIII Summer School A. Corbella , pp. 7-32. Societa Chimica Italiana, MUan. 

Likewise, an efficient one-pot multicomponent synthesis of annelated 2-amino pyridines (e.g., 17) utilizing [4+2] cycloadditions has been described <06JOC3494>. The process involves the in situ generation of 1-aza-1,3-butadiene from a palladium-catalyzed coupling-isomerization reaction of aryl halides (e.g., 18) with propargyl V-tosylamines (e.g., 19). The resulting butadiene then undergoes cycloadditions with V.S -ketene acetals (e.g., 20) to form annelated pyridines (e.g., 17). 

In an extension of traditional Stetter methodology, Miiller and co-workers have used the Stetter reaction in a one-pot multicomponent reaction for the synthesis of furans and pyrroles (Scheme 19) [85,86], The ot,P-unsaturated ketone XXVI is formed in situ and undergoes a Stetter reaction followed by a Paal-Knorr condensation. 

Bohn Rhoden CR, Westermann B, Wessjohann LA (2008) One-pot multicomponent synthesis of N-substituted tryptophan-derived diketopiperazines. Synthesis (Stuttg) 13 ... 

Rhoden CRB, Westermann B, Wessjoharm LA (2008) One-pot multicomponent synthesis of N-substituted tryptophan-derived diketopiperazines. Synthesis (Stuttg) (13) 2077-2082 Szardenings AK, Burkoth TS, Lu HH, Tien DW, Campbell DA (1997) A simple procedure for the solid phase synthesis of diketopiperazine and diketomorpholine derivatives. Tetrahedron 53(19) 6573-6593... 

Because of our interest in one-pot, multicomponent annulations,7 we envisioned a flexible and efficient protocol which would link the four different components via the formation of four new bonds (a-d, eq. 1) in one reaction vessel. The intermediate 7-hydroxystannanes thus formed in eq. 1 could be oxidatively fragmented8 to produce both ring enlargement and regiospecific formation of an alkenyl unit. This 4-atom ring expansion methodology of common sized a,p-unsaturated ketones has led to the syntheses of many mono- and disubstituted 9-, 10-, and 11-membered unsaturated macrolides (Table ). 

Some new oxadiazepines have been reported to be obtained by a one-pot multicomponent reaction. Reaction of (iV-isocyanimino)triphenylphosphorane (CNNPPhj) 211 with dialkylacetylenedicarboxylates 212 and... 

More recently, Porta and co-workers [6] applied similar considerations of the polar effects to a new one-pot multicomponent process for the addition of nucleophilic radicals to aldimines, generated in situ in the presence of Ti(IV). In analogy with the Minisci reaction, Ti(IV), which acts as a Lewis acid, coordinates the nitrogen of the imine, strongly increasing the electron-deficient character of the carbon in the a-posilion and thus the reactivity of the imine toward nucleophilic radicals. This reaction, as well as the Minisci one, represents a useful route for the synthesis of a variety of poly-functionalized derivatives of chemical and biochemical relevance. 

The librariesPPl of U-4CR products already mentioned in 1961,were not prepared until 1995. Since then, this approach has found widespread application in industrial chemical research. It is expected that this one-pot, multicomponent approach will play an essential role in synthetic organic strategies in the future.P 1... 

D. Kahne et al. developed a one-pot multicomponent stereoselective synthesis for the trisaccharide portion of cyclamycin 0 using the Kahne glycosidation.The reactivity of the glycosyl donor was tuned (the rate limiting step is the triflation of the sulfoxide) and the p-methoxyphenyl sulfoxide was activated first. The trisaccharide was obtained in an overall 25% yield with complete a-selectivity. 

Chen L, Huang XJ, Li YQ, Zhou MY, Zheng WJ (2009) A one-pot multicomponent reaction for the synthesis of 2-amino-2-chromenes promoted by N, N-dimethylamino-functionalized basic ionic liquid catalysis under solvent-free condition. Monatsh fUr Chem 140 45 7... 

The use of ionic liquids in numerous organic transformations ranging from one-step to one-pot multicomponent reactions had been documented in the literature. In this account, we will provide a brief overview of some of the recent advancements in this area and depict that ionic liquids are indeed versatUe green solvents in organic synthesis. 

Potentially useful heterocyclic libraries can also be prepared by the application of solution-phase combinatorial chemistry. Although multiple reactions in solution have often been complicated by the difficulties with liquid-liquid extractions the introduction of solid scavengers and equipment to automate these extraction processes allows hundreds of reactions to be managed simultaneously. A typical example is a series of aminothiazole derivatives which has been prepared starting from acyclic precursors (Scheme 3.9). Naturally one-pot multicomponent condensations such as the Ugi (library 84) [332], Passerini or Biginelli reactions present one of the simplest... 

This reaction was first reported by Robinson in 1917 and subsequently improved by Schopf in 1935. It is an ingenious one-pot multicomponent synthesis of tropinone from succindialdehyde, acetonedicarboxylic acid and methylamine in aqueous solution involving a double Mannich Reaction This reaction is thus known as the Robinson tropinone synthesis," Robinson synthesis, " Robinson-Schopf reaction,Robinson-Schopf condensation, or Robinson condensation." It has been reported that the Robinson tropinone synthesis can take place without any racemization at the stereogenic center adjacent to the aldehyde group, as demonstrated by the formation of L-a/to-teloidinone from D-tartaraldehyde, and c-a/to-teloidinone from i-tartaraldehyde respectively." ... 

The four-component reaction of ethyl acetoacetate, hydrazine hydrate, malononitrile and various aldehydes using L-Pro (10 mol%) as catalyst affords a series of 2,4-dihydropyrano-[2,3-c]-p5Tazoles (Scheme 2.12). Polysubstituted tetrahydropyridines were eoneisely synthesised in a one-pot multicomponent reaction between aromatie allgmones, aliphatic amines, active methylene compounds and formaldehyde (Scheme 2.12). ... 

Polystyrene supported versions of catalyst Id have been reported/ In addition, Frechet and coworkers demonstrated that catalyst Id can be encapsulated in the core of a soluble star polymer, which enables reagents to diffuse, allowing catalysis to take place/ Interestingly, the concurrent mixing of different chiral and achiral catalysts encapsulated in a similar manner onto different star polymers enabled one-pot multicomponent asymmetric cascade reactions of otherwise incompatible catalysts. 

Ariga and coworkers reported the synthesis of polyfunctionahzed isoxazolines 184 via acylation of dinitronate 187 followed by intramolecular cychzation via a one-pot multicomponent reaction (Scheme 46) [147]. The sequence involves conversion of pyridiniiun salt of 4-nitroisoxazoUn-5(2H)-one... 

Synthesis of triazole-based unnatural amino acids via microwave-assisted regioselective one-pot multicomponent reactions ofsulfamidates 13COC 2323. 

A one-pot multicomponent cascade reaction of arylamines, aldehydes, and electron-deficient dienophiles on a soluble support under microwave conditions has been reported to involve a base-catalysed Povarov reaction and a [l,3]-sigmatropic rearrangement leading to 4,10-dihydropyrimido[l,2-fl]benzimidazoles (Scheme 17). ... 

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