Total synthesis of (-)-cocaine and (-)-ferruginine

Iodide-Mediated [3 + 2]-Cycloaddition Reaction with N-Tosylaziridines and α,β-Unsaturated Ketones

The [3 + 2]-cycloaddition reaction between N-tosylaziridines and α,β-unsaturated ketones was promoted with lithium iodide. The reaction proceeded under mild conditions to provide N-tosylpyrrolidines. Quaternary carbon-possessing 3,3-disubstituted pyrrolidines including spiro compounds were afforded in high yields. A simple procedure with easy to handle reagents makes this reaction concise. The intramolecular version of this reaction was applied to synthesize tropane skeletons.

Engaging DBFO as a C1N1 “two-atom synthon” in [3 + 2] cycloaddition reaction: synthesis of the energetic material 5-azidotetrazolate 1N-oxide

Employing 1,1-dibromoformaloxime as a novel C1N1 “two-atom synthon” for the synthesis of tetrazole-based energetic materials via an intramolecular [3 + 2] annulation in aqueous solution.

Stereoselective Synthesis of Tropanes via a 6π-Electrocyclic Ring-Opening/ Huisgen [3+2]-Cycloaddition Cascade of Monocyclopropanated Heterocycles

The synthesis of tropanes via a microwave-assisted, stereoselective 6π-electrocyclic ring-opening/ Huisgen [3+2]-cycloaddition cascade of cyclopropanated pyrrole and furan derivatives with electron-deficient dipolarophiles is demonstrated. Starting from furans or pyrroles, 8-aza- and 8-oxabicyclo[3.2.1]octanes are accessible in two steps in dia- and enantioselective pure form, being versatile building blocks for the synthesis of pharmaceutically relevant targets, especially for new cocaine analogues bearing various substituents at the C-6/C-7 positions of the tropane ring system. Moreover, the 2-azabicyclo[2.2.2]octane core (isoquinuclidines), being prominently represented in many natural and pharmaceutical products, is accessible via this approach.

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.

Synthesis of the [7-5-5] tricyclic core of Daphniphyllum alkaloids

The [7-5-5] tricyclic core of the Daphniphyllum alkaloids was constructed, featuring a Claisen-Ireland rearrangement to install the two contiguous stereogenic centers, E1cB elimination to form the tetrasubstituted C–C double bond, and a 2,3-Wittig rearrangement to construct the quaternary carbon.

Recent advances on the total synthesis of alkaloids in mainland China

Alkaloids are a large family of natural products that mostly contain basic nitrogen atoms. Because of their intriguing structures and important functions, they have long been popular targets for synthetic organic chemists. China's chemists have made significant progress in the area of alkaloid synthesis over past decades. In this article, selected total syntheses of alkaloids from research groups in mainland China during the period 2011–16 are highlighted.

Iterative direct C(sp3)–H functionalization of amines: diastereoselective divergent syntheses of α,α′-disubstituted alicyclic amines

Facile access to the syn-α,α′-disubstituted N-heterocycles via iterative C–H oxygenation and C–C bond formation.

Construction of the tricyclic core of steenkrotin-type diterpenoids via intramolecular [3 + 2] cycloaddition

A concise and diastereoselective route to the [5–6–7] tricyclic skeleton of steenkrotins was developed based on an intramolecular [3 + 2] cycloaddition.

Construction of an all-substituted pyrrolidine derivative with multiple stereogenic centers and Betti-base-derived γ-amino alcohols by [1,2]-Wittig rearrangement

The construction of Betti base-derived γ-amino alcohols and all-substituted pyrrolidine derivative with multiple stereogenic centers has been developed successfully through neighboring lithium-assisted [1,2]-Wittig rearrangement (NLAWR).

The origin for highly enantioselective induction of 1-naphthol to isatin-derived N-Boc ketimines catalyzed by quinine thiourea catalyst: an experimental and computational study

An enantioselective aza-Friedel–Crafts reaction of 1-naphthol with isatin derived N-Boc ketimines by cinchona based bifunctional thiourea as organo-catalyst is reported.

Switchable stereocontrolled divergent synthesis induced by aza-Michael addition of deactivated primary amines under acid catalysis

Switchable tandem intramolecular aza-Michael/Michael and double aza-Michael reactions allow the oriented synthesis of highly functionalised cyclic skeletons. Conjugate addition of deactivated anilines triggers chemo- and stereo-divergent ring-closure reaction pathways with a striking selectivity depending on reaction conditions.

Stereoselective synthesis of cis-2,5-disubstituted pyrrolidines via Wacker-type aerobic oxidative cyclization of alkenes with tert-butanesulfinamide nucleophiles

Palladium(II)-catalyzed aerobic oxidative cyclization of alkenes with tethered tert-butanesulfinamides furnishes enantiopure 2,5-disubstituted pyrrolidines, originating from readily available and easily diversified starting materials. These reactions are the first reported examples of metal-catalyzed addition of sulfinamide nucleophiles to alkenes.

Enantioselective synthesis of cocaine C-1 analogues using sulfinimines (N-sulfinyl imines)

The first examples of cocaine analogues having substituents (methyl, ethyl, n-propyl, n-pentyl, and phenyl) at the C-1 position of the cocaine tropane skeleton were prepared by heating sulfinimine-derived α,β-unsaturated pyrrolidine nitrones. In the presence of the Lewis acid Al(O(t)Bu)(3) the nitrones undergo an intramolecular [3 + 2] cycloaddition to give tricyclic isoxazolidines that were transformed in three steps to the cocaine analogues. In the absence of the Lewis acid, lactams were formed resulting from rearrangement of the nitrone to an oxaziridine. A novel Pd- and base-promoted rearrangement of methanesulfonate salts of isoxazolidine to bridge bicyclic[4.2.1]isoxazolidines was discovered.

Total syntheses of (-)-hanishin, (-)-longamide B, and (-)-longamide B methyl ester via a novel preparation of N-substituted pyrrole-2-carboxylates [corrected]

A novel preparation of N-substituted pyrrole-2-carboxylates has been developed based upon 1,3-dipolar cycloaddition and a conventional hydrogenolysis. By using this method as the key step, total syntheses of natural alkaloids (-)-hanishin, (-)-longamide [corrected] B, and (-)-longamide [corrected] B methyl ester were accomplished in the highest overall yields, respectively.

An approach to mimicking the sesquiterpene cyclase phase by nickel-promoted diene/alkyne cooligomerization

Artificially mimicking the cyclase phase of terpene biosynthesis inspires the invention of new methodologies, since working with carbogenic frameworks containing minimal functionality limits the chemist's toolbox of synthetic strategies. For example, the construction of terpene skeletons from five-carbon building blocks would be an exciting pathway to mimic in the laboratory. Nature oligomerizes, cyclizes, and then oxidizes γ,γ-dimethylallyl pyrophosphate (DMAPP) and isopentenyl pyrophosphate (IPP) to all of the known terpenes. Starting from isoprene, the goal of this work was to mimic Nature's approach for rapidly building molecular complexity. In principle, the controlled oligomerization of isoprene would drastically simplify the synthesis of terpenes used in the medicine, perfumery, flavor, and materials industries. This article delineates our extensive efforts to cooligomerize isoprene or butadiene with alkynes in a controlled fashion by zerovalent nickel catalysis building off the classic studies by Wilke and co-workers.

Facile and enantiospecific syntheses of (6S,7R)-6-chloro-7-benzyloxy-, (7S)-halo-, and (7S)-hydroxy-cocaine and natural (-)-cocaine from D-(-)-ribose

First syntheses of C6,7 and C7 enantiopure cocaine analogues were achieved from D-(-)-ribose via a trans-acetonide controlled endo-selective intramolecular nitrone-alkene cycloaddition (INAC) as the key step. This synthetic scheme allows practical preparation of cocaine analogues for bioevaluation as potential candidates for the treatment of cocaine addiction and as potential conjugates for immunotherapy.