Concise Catalytic Asymmetric Total Synthesis of Biologically Active Tropane Alkaloids

Recent progress in the synthesis of homotropane alkaloids adaline, euphococcinine and N-methyleuphococcinine

The 9-azabicyclo[3.3.1]nonane ring system is present in several insect- and plant-derived alkaloids. (-)-Adaline (1) and (+)-euphococcinine (2), found in secretions of Coccinelid beetles, and (+)-N-methyleuphococcinine (3), isolated from the Colorado blue spruce Picea pungens, are members of this alkaloid family. Their unique bicyclic system with a quaternary stereocenter, and the potent biological activity exerted by these homotropane alkaloids, make them attractive synthetic targets. This work aims briefly to review the chemical ecology of Adalia bipunctata and the recent methodologies to obtain adaline (1), euphococcinine (2), and N-methyleuphococcinine (3).

Advances in the Asymmetric Total Synthesis of Natural Products Using Chiral Secondary Amine Catalyzed Reactions of α,β-Unsaturated Aldehydes

Chirality is one of the most important attributes for its presence in a vast majority of bioactive natural products and pharmaceuticals. Asymmetric organocatalysis methods have emerged as a powerful methodology for the construction of highly enantioenriched structural skeletons of the target molecules. Due to their extensive application of organocatalysis in the total synthesis of bioactive molecules and some of them have been used in the industrial synthesis of drugs have attracted increasing interests from chemists. Among the chiral organocatalysts, chiral secondary amines (MacMillan's catalyst and Jorgensen's catalyst) have been especially considered attractive strategies because of their impressive efficiency. Herein, we outline advances in the asymmetric total synthesis of natural products and relevant drugs by using the strategy of chiral secondary amine catalyzed reactions of α,β-unsaturated aldehydes in the last eighteen years.

DARK Classics in Chemical Neuroscience: Cocaine

In this Review, we consider the story of cocaine from its humble origins in South America to its status as one of the most abused substances in 21st century society. The synthesis and biosynthesis of cocaine are discussed, as well as its pharmacokinetics, metabolism, pharmacology, and importance in modern neuroscience and molecular imaging.

The Chemical Synthesis and Applications of Tropane Alkaloids

Tropanes are an important class of alkaloid natural products that are found in plants all over the world. These compounds can exhibit significant biological activity and are among the oldest known medicines. In the early 19th century, tropanes were isolated, characterized, and synthesized by notable chemical researchers. Their significant biological activities have inspired tremendous research efforts toward their synthesis and the elucidation of their pharmacological activity both in academia and in industry. In this chapter, which addresses the developments in this field since 1994, the focus is on the synthesis of these compounds, and several examples of sophisticated synthetic protocols involving both asymmetric and catalytic approaches are described. In addition, the structures of more than 100 new alkaloids are included as well as the applications and pharmacological properties of some tropane alkaloids.

Alkaloid Synthesis Using Organocatalysts

This chapter covers the literature since the advent, in the 21st century, of total syntheses of alkaloids using enantio- or diastereoselective organocatalytic reactions to construct the alkaloid scaffolds. The details of these alkaloid syntheses are described separately for each basic skeleton, including indole, indoline, oxindole, and piperidine alkaloids.

An orthogonally protected CycloTriVeratrylene (CTV) as a highly pre-organized molecular scaffold for subsequent ligation of different cyclic peptides towards protein mimics

The synthesis of a semi-orthogonally protected CycloTriVeratrilene (CTV) scaffold derivative as well as the sequential introduction of three different peptide loops onto this molecular scaffold via Cu(I)-catalyzed azide alkyne cycloaddition towards a medium-sized protein mimic is described. This approach for the construction of medium-sized protein mimics is illustrated by the synthesis of a paratope mimic of the monoclonal antibody Infliximab (Remicade®) and provides access to a range of highly pre-organized molecular constructs bearing three different peptide segments. This approach may find wide applications for development of protein-protein interaction disruptors as well as synthetic vaccines.

Alkaloid synthesis using chiral secondary amine organocatalysts

The full strategies of alkaloid syntheses which contain asymmetric organocatalytic reaction for construction of these scaffolds is discussed.

Combined heterogeneous metal/organic catalysts for eco-friendly synthesis

The interplay and synergistic cooperation between homogeneous and heterogeneous catalyst systems is of utmost importance in nature. It is also applied in chemical synthesis. Here, it can allow for new reactivity, which is not possible by the employment of a single catalyst, and promote the catalysis of multiple transformations in a one-pot sequence. This could overall lead to novel reactions and the development of sustainable chemistry. In this context, a versatile and broad synergistic strategy for the selective synthesis of valuable molecules with variable complexity and under eco-friendly conditions is disclosed. It is based on integrated heterogeneous metal/organo multiple relay catalysis, which is performed in a single reaction vessel, and allows for the assembly of complex molecules (e.g., heterocycles and carbocycles) with up to three quaternary stereocenters in a highly enantioselective fashion from simple alcohols and air/O2.