Total Syntheses of Discoipyrroles A, B, and C, Three Marine Natural Products

Herein, we describe our efforts culminating in the total syntheses of discoipyrroles A, B, and C in 6, 6, and 7 steps respectively with excellent overall yield. Total syntheses of these unique natural products have been accomplished involving microwave-mediated Paal-Knorr pyrrole synthesis, Pd-catalyzed carbonylative transformation, and MoOPH (Vedejs reagent) oxidation as key reactions to construct the 1,2,3,5-tetrasubstituted pyrrole and oxidative cyclization of highly substituted pyrrole as key steps.

Synthetic studies on palmerolide C: synthesis of an advanced intermediate towards the revised structure of palmerolide C

A stereoselective synthesis of the highly advanced intermediates towards the revised structure of palmerolide C and 10-epi-palmerolide C is described in this paper. The required key fragments C1-C6, C7-C14 and C15-C23 have been successfully assembled in a convergent manner to access the C1-C23 framework bearing all the five stereocenters present in the natural product. The synthesis involves the Julia-Kocienski reaction, Yamaguchi esterification, Takai olefination and regioselective epoxide opening as key steps. The proposed route is flexible and could also be applied to the synthesis of structurally related palmerolides.

Synthetic approaches towards cortistatins: evolution and progress through its ages

Cortistatins are a family of steroidal alkaloids with a unique pentacyclic skeleton, having immensely potent anti-angiogenetic activities. Given the scarcity in the natural availability of these compounds, their syntheses became major attractions in organic chemistry. Along with total synthesis of the most potent congeners in the family: cortistatins A and J, the synthesis of two other members have been successfully completed, while various other analogues have also been designed with variable degrees of biological activities. This review is an exhaustive coverage of the significant attempts towards constructing this highly challenging molecule and also aims to highlight the deep understanding of the structure-activity relationships of these compounds, which have been garnered over time.

Construction of key building blocks towards the synthesis of cortistatins

This work reports the construction of key building blocks towards the synthesis of cortistatins; a family of steroidal alkaloids. Cortistatin A, being a primary target due to its superior biological properties over other congeners, has been prepared by two different synthetic routes. Synthesis of the precursor to the heavily substituted A-ring starting from d-glucose and construction of the DE-ring junction employing a Hajos-Parrish ketone as a chiral pool have been demonstrated. Efforts are underway to assemble these key fragments and build towards the total synthesis of cortistatin A.

Short Enantioselective Formal Synthesis of (-)-Platencin

A short enantioselective formal synthesis of the antibiotic natural product platencin is reported. Key steps in the synthesis include enantioselective decarboxylation alkylation, aldehyde/olefin radical cyclization, and regioselective aldol cyclization.

Recent advances in the synthesis of natural multifunctionalized decalins

This review highlights recent innovative synthetic strategies developed for the stereoselective construction of natural complex decalin systems. It offers an insight into various synthetic targets and approaches and provides information for developments within the area of natural products as well as synthetic methodology.

A concise formal synthesis of platencin

A formal synthesis of platencin features an organocatalytic approach to the [2.2.2] bicycle, a radical reductive elimination, a Au-catalyzed rearrangement and a Rh-catalyzed hydrosilylation.

Enantioselective synthesis of bicyclo[2.2.2]octane-1-carboxylates under metal free conditions

A new tandem reaction permits rapid access to bicyclo[2.2.2]octane-1-carboxylates with excellent enantioselectivities under metal free, mild, and operationally simple conditions.

A new route to platencin via decarboxylative radical cyclization

A new approach to platencin, a potent antibiotic isolated from Streptomyces platensis, has been established. The highly congested tricyclic core of the natural product was successfully constructed by decarboxylative radical cyclization of an alkynyl silyl ester with Pb(OAc)4 in the presence of pyridine in refluxing 1,4-dioxane. The key decarboxylation, which likely takes place via lead(IV) esterification followed by carbon-centered radical generation and subsequent capture of the radical with a triple bond, allows the rapid construction of the twisted polycyclic system.