Total Synthesis of (-)-Enigmazole B

Yamaguchi esterification: a key step toward the synthesis of natural products and their analogs-a review

The Yamaguchi reagent, based on 2,4,6-trichlorobenzoyl chloride (TCBC) and 4-dimethylaminopyridine (DMAP), is an efficient tool for conducting the intermolecular (esterification) reaction between an acid and an alcohol in the presence of a suitable base (Et3N or i Pr2NEt) and solvent (THF, DCM, or toluene). The Yamaguchi protocol is renowned for its ability to efficiently produce a diverse array of functionalized esters, promoting high yields, regioselectivity, and easy handling under mild conditions with short reaction times. Here, the recent utilization of the Yamaguchi reagent was reviewed in the synthesis of various natural products such as macrolides, terpenoids, polyketides, peptides, and metabolites.

Gold-catalyzed cyclization and cycloaddition in natural product synthesis

Covering: 2016 to mid 2023Transition metal catalysis, known for its remarkable capacity to expedite the assembly of molecular complexity from readily available starting materials in a single operation, occupies a central position in contemporary chemical synthesis. Within this landscape, gold-catalyzed reactions present a novel and versatile paradigm, offering robust frameworks for accessing diverse structural motifs. In this review, we highlighted a curated selection of publications in the past 8 years, focusing on the deployment of homogeneous gold catalysis in the ring-forming step for the total synthesis of natural products. These investigations are categorized based on the specific ring formations they engender, accentuating the prevailing gold-catalyzed methodologies applied to surmount intricate challenges in natural products synthesis.

Total Synthesis of (-)-Enigmazole A by the Macrocyclization/Transannular Pyran Cyclization Strategy

An 18-step synthesis of (-)-enigmazole A is herein disclosed. The present synthesis is based on a modular assembly of three building blocks of similar complexity, a macrocyclic ring-closing metathesis to forge the 18-membered macrocyclic skeleton, and a desilylative transannular oxa-Michael addition for stereoselective construction of the 2,6-cis-substituted tetrahydropyran ring.