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David Tejedor

Publications and source records attributed to David Tejedor.

9 recordsLinked to original sources
PubMed2007

A substrate-based folding process incorporating chemodifferentiating ABB' three-component reactions of terminal alkynoates and 1,2-dicarbonyl compounds: a skeletal-diversity-oriented synthetic manifold.

A novel three-component reaction (3CR)-based folding process that is able to generate complexity and skeletal diversity is described. The process utilizes chemodifferentiating organocatalyzed ABB' 3CRs of a terminal conjugated alkynoate (building block) with alpha-dicarbonyl compounds (diversity-generating blocks) to generate an array of different molecular topologies (gamma-lactones, linear propargylic enol ethers, or 1,3-dioxolane rings). Amides and esters behave as efficient reactivity-encoding elements (sigma) of the attached keto functionality. Three chemical properties govern the chemical outcome of this folding process: acidity, nucleophilicity (of the catalyst), and carbonyl electrophilicity. Overall, this substrate-based folding process generates three different molecular architectures from the same modular functionalities (ketones) and under the same reaction conditions (methyl propiolate and tertiary amine). In addition, and very importantly for combinatorial applications, all of the products share a common reactive functionality that allows them to be collective substrates for a subsequent diversity-generating process.

Journal Article↗
PubMed2005

Multicomponent domino processes based on the organocatalytic generation of conjugated acetylides: efficient synthetic manifolds for diversity-oriented molecular construction.

The organocatalytic generation of a strong base by the action of a good nucleophile is the base for the in situ catalytic generation of conjugated acetylides in the presence of aldehydes or activated ketones. The method is affordable in a multicomponent, domino format able to generate a chemically diverse set of multifunctionalized adducts that are very well suited for diversity-oriented molecular construction. The domino process involves a nucleophile as catalyst and a terminal conjugated alkyne (H-C[triple chemical bond]C-Z) and an aldehyde or activated ketone as building blocks. The chemical outcome of this process changes dramatically as a function of the nucleophile (tertiary amine or phosphine), temperature, stoichiometry, and solvent. These multicomponent domino processes achieve molecular construction with good atom economy and, very importantly, with an exquisite chemo-differentiating incorporation of identical starting units into the products (nondegenerated chemical output). These properties convert the H-C[triple chemical bond]C-Z unit into a specific building block for diversity-oriented molecular construction. Applications to the modular and diversity-oriented synthesis of relevant heterocycles are discussed. A protocol involving two coupled domino processes linked in a one-pot manner will be discussed as an efficient synthetic manifold for the modular and diversity-oriented construction of multisubstituted nitrogen-containing heterocycles.

Aldehydes↗
PubMed2005

Antiproliferative activity in HL60 cells by tetrasubstituted pyrroles: a structure-activity relationship study.

A number of tetrasubstituted pyrrole derivatives have been synthesized and evaluated for their in vitro antiproliferative activities using the human promyelocytic leukemia cell line HL60. Tetrasubstituted pyrroles are obtained by irradiation of a silica gel absorbed mixture of a conjugated alkynoate and a primary amine. Active compounds exhibited GI50 values in the range 4-45 microM, and only six products showed TGI values within the evaluation range. A structure-activity relationship is also discussed.

Cell Division↗
PubMed2005

A modular, one-pot, four-component synthesis of polysubstituted 1,3-oxazolidines.

A modular, one-pot, two-step, four-component synthesis of polysubstituted 1,3-oxzolidines is described. The method comprises two linked domino processes: an organocatalyzed domino reaction of alkyl propiolate and an aliphatic aldehydes and a microwave-assisted amine addition cyclization domino process. An alternative modular, one-pot, three-step, four-component synthesis has also been developed by linking the organocatalyzed domino process to a sequential amine addition/Yb(OTf)(3)-catalyzed enamine cyclization reaction.

Oxazoles↗
PubMed2004

A diversity-oriented strategy for the construction of tetrasubstituted pyrroles via coupled domino processes.

A new microwave-assisted rearrangement of 1,3-oxazolidines scaffolds is the basis for a new, metal-free, direct, and modular construction of tetrasubstituted pyrroles from terminal-conjugated alkynes, aldehydes, and primary amines. This new reaction manifold entails two linked domino processes in a one-pot manner with both atom- and bond-efficiency and under very simple and environment-friendly experimental conditions.

Journal Article↗
PubMed2003

Efficient domino process based on the catalytic generation of non-metalated, conjugated acetylides in the presence of aldehydes or activated ketones.

The extremely mild and highly efficient catalytic generation of non-metalated, conjugated acetylides is reported. These acetylides are used to generate enol-protected functionalized propargylic alcohols 1, 1,3-dioxolane compounds 2, or 3,4,5-trisubstituted 4,5-dihydrofurans 4 through serial multibond-forming processes. The method calls for a nucleophile (a tertiary amine or phosphine) as a chemical activator, a conjugated terminal acetylene as the acetylide source, and an aldehyde or activated ketone as the electrophilic partner. The chemical outcome of this process depends on the nature of the nucleophile, the temperature, stoichiometry and solvent, and it can be tailored selectively by the appropriate choice of the experimental conditions.

Aldehydes↗