Asymmetric synthesis of N,O-diacetyl-3-epi-xestoaminol C: structure and absolute configuration confirmation of 3-epi-xestoaminol C

Microgrewiapine C: Asymmetric Synthesis, Spectroscopic Data, and Configuration Assignment

The first asymmetric synthesis of microgrewiapine C, a piperidine alkaloid isolated from Microcos paniculata, is reported. This synthesis prompted correction of the 1H and 13C NMR data for the natural sample of the alkaloid, which was achieved by reanalysis of the original spectra. The corrected data for the natural product were found to be identical to those of the synthetic sample prepared herein, thus confirming the structural and relative configurational assignment of microgrewiapine C. Although comparison of specific rotation values indicates that the (1R,2S,3S,6S) absolute configuration should be assigned to the alkaloid, consideration of potential common biosynthetic origins of microgrewiapine C and congeners suggests that further phytochemical investigations are warranted.

Homoallylic amines as efficient chiral inducing frameworks in the conjugate addition of amides to α,β-unsaturated esters. An entry to enantio-enriched diversely substituted amines

The diastereoselective conjugate addition of secondary homoallylamines, obtained in the enantioenriched form via allylmetallation of imines, to α,β-unsaturated esters is reported. This method allows access to valuable building blocks as well as heterocyclic skeletons, providing tertiary amines bearing two chains integrating a stereogenic center adjacent to the nitrogen atom.

An Acetylenic Lipid from the New Zealand Ascidian Pseudodistoma cereum: Exemplification of an Improved Workflow for Determination of Absolute Configuration of Long-Chain 2-Amino-3-alkanols

An acetylenic 2-amino-3-alcohol, distaminolyne B (2), isolated from the New Zealand ascidian Pseudodistoma cereum, is reported. The isolation and structure elucidation of 2 and assignment of 2S,3S absolute configuration (AC) using the exciton coupled circular dichroism technique are described. Using a methodologically facile workflow, the same AC was also established by analysis of specific rotation, terminal methyl C-1 δ_C chemical shift, and NH δ_H and J values of the N,O-diacetate derivative.

Total synthesis and the anticancer activity of (+)-spisulosine

The total synthesis of the anticancer agent (+)-spisulosine has been accomplished. The strategy involved a substrate-controlled aza-Claisen rearrangement to establish the erythro-configured amino-alcohol motif followed by deoxygenation to create a methyl side-chain. Subsequent Wittig olefination then permitted the construction of the carbon backbone of the target molecule. To investigate the antiproliferative effect of 1, its biological profile was examined on a panel of 6 human malignant cell lines and demonstrated the significant anticancer activity of 1 on at least five of the evaluated lines with IC₅₀ < 1 μM (MCF-7, HTC-116, Caco-2, Jurkat and HeLa).