Stereoselective alkenylation of aldehydes with phosphorus carbanions: Preparation of E- and Z-2-alkoxy- and 2-aryloxy-2-alkenoates

A Nonoxidative Sequence for the Preparation of 1,2-Diketone Derivatives Using Aldehyde and Organometallic Building Blocks

This study investigates a synthetic sequence for the preparation of 1,2-diketone products. The sequence avoids oxidative conditions and instead employs reliable transformations including the Horner-Wadsworth-Emmons and addition of Grignard reagents to N-methyl-N-methoxy (Weinreb) amide intermediates. The reaction sequence is suitable for the synthesis of nonsymmetric aliphatic and aryl substituted derivatives.

Total synthesis of tubulysin U and N14-desacetoxytubulysin H

A concise and efficient procedure for the total synthesis of tubulysin U and N14-desacetoxytubulysin H has been developed with high stereoselectivity on a gram scale. This synthesis features an elegant cascade one-pot process to install the challenging thiazole moiety and the employment of stereoselective reductions and a series of high-yield mild reactions to ensure the requisite stereochemistry, reaction scale, and yield and to avoid the vexing epimerization occurring during peptide formation.

Synthesis of 2-aryloxy butenoates by copper-catalysed allylic C–H carboxylation of allyl aryl ethers with carbon dioxide

2-Aryloxy butenoates were efficiently synthesized by deprotonative alumination of ally aryl ethers and subsequent Cu-catalysed carboxylation with CO₂.

Total syntheses of (+)-vigulariol and (-)-sclerophytin A

The total syntheses of (+)-vigulariol and (-)-sclerophytin A are reported in 15 steps and 16 steps, respectively, from a known compound. The flexible, readily scalable synthetic strategy allows for rapid construction of a critical tricyclic intermediate and is demonstrated via the synthesis of these two marine natural products. A key reaction in this synthetic protocol is a combination Wittig/intramolecular Diels-Alder cycloaddition.

Total synthesis of the proposed structure of briarellin J

The total synthesis of the originally proposed structure of briarellin J is reported in 15 steps from a known compound and in 23 steps from readily available materials. Key reactions include an exo-selective intramolecular Diels-Alder and a substrate-controlled hydroboration. Discrepancies in the spectroscopic data of the synthetic and natural material led to a revision of the assigned structure.