A stereocontrolled route to d-ribo-phytosphingosine and sphinganine from an achiral secondary homoallylic alcohol using Sharpless kinetic resolution

Synthesis of 1-Substituted Bicyclo[2.1.1]hexan-2-ones via a Sequential SmI2-Mediated Pinacol Coupling and Acid-Catalyzed Pinacol Rearrangement Reaction

A two-step procedure, combining a SmI2-mediated transannular pinacol coupling reaction with an acid-catalyzed pinacol rearrangement process, was employed to prepare a diverse range of 1-substituted bicyclo[2.1.1]hexan-5-ones from cyclobutanedione derivatives. To underscore the significance of these bicyclic ketones in drug synthesis, an sp3-rich analog of nitazoxanide, a well-known antiparasitic and antiviral agent, was synthesized.

Synthesis and Biological Activity of 2-(2-Amino-2-phenylethyl)-5-oxotetrahydrofuran-2-carboxylic Acid: A Microwave-Assisted 1,3-Dipolar Cycloaddition Approach

The microwave-assisted 1,3-dipolar cycloaddition of furanyl and benzyl oximes and several methyl acrylates effectively provided several isoxazoline when mediated by diacetoxyiodobenzene. The selected isoxazoline, methyl-5-(3-methoxy-3-oxopropyl)-3-phenyl-4,5-dihydro isoxazole-5-carboxylate, was rapidly transformed to the γ-lactone carboxylic acid, 2-(2-amino-2-phenylethyl)-5-oxotetrahydrofuran-2-carboxylic acid, in reasonable yield. The biological activity of this γ-lactone carboxylic acid increased the growth of E. coli organisms by about 44% and has a potential significance in stem cell research.

Stereoselective synthesis and antiproliferative activity of the isomeric sphinganine analogues

A flexible synthetic approach to biologically active sphingoid base-like compounds with a 3-amino-1,2-diol framework was achieved through a [3,3]-sigmatropic rearrangement and late stage olefin cross-metathesis as the key transformations. The stereochemistry of the newly created stereogenic centre was assigned via a single crystal X-ray analysis of the (4S,5R)-5-(hydroxymethyl)-4-vinyloxazolidine-2-thione. In order to rationalise the observed stereoselectivity of the aza-Claisen rearrangement, DFT calculations were carried out. The targeted isomeric sphingoid bases were screened in vitro for anticancer activity on a panel of seven human malignant cell lines. Cell viability experiments revealed that C₁₇-homologues are more active than their C₁₂ congeners.

‘Chiron’ approach to stereoselective synthesis of sphinganine and unnatural safingol, an antineoplastic and antipsoriatic agent

Highly stereoselective total syntheses of sphinganine 1 and antineoplastic and antipsoriatic drug safingol 17 have been demonstrated.

Preparation of anti-vicinal amino alcohols: asymmetric synthesis of D-erythro-sphinganine, (+)-spisulosine, and D-ribo-phytosphingosine

Two variations of the Overman rearrangement have been developed for the highly selective synthesis of anti-vicinal amino alcohol natural products. A MOM ether-directed palladium(II)-catalyzed rearrangement of an allylic trichloroacetimidate was used as the key step for the preparation of the protein kinase C inhibitor D-erythro-sphinganine and the antitumor agent (+)-spisulosine, whereas the Overman rearrangement of chiral allylic trichloroacetimidates generated by the asymmetric reduction of an α,β-unsaturated methyl ketone allowed rapid access both to D-ribo-phytosphingosine and L-arabino-phytosphingosine.