15-Fluoro prostaglandin FP agonists: a new class of topical ocular hypotensives

Photoinduced Iron-Catalyzed Decarboxylation/Isomerization of gem-Difluoroallyl Carboxylic Acid to Access Vinyl Difluoromethylene Units

Vinyl difluoromethylene units (-CF-) significantly enhance the bioactivity and physical and chemical properties of compounds. Despite recent advances in introducing vinyl difluoromethylene units, radical-mediated formation of these motifs remains largely unexplored. A novel serial catalytic strategy for selective defluoroalkylation of trifluoromethyl alkenes has been developed, utilizing photocatalytic defluorocarboxylation followed by photoinduced iron-catalyzed decarboxylation/isomerization. The defluoroalkylation reaction involves generating difluoroallyl radicals, tautomerizing to vinyl difluoromethylene radicals, and proceeding through radical addition and alkylation.

Stereoselective synthesis of an advanced trans-decalin intermediate towards the total synthesis of anthracimycin

Progress towards the total synthesis of the macrolide natural product anthracimycin is described. This new approach utilises an intermolecular Diels-Alder strategy followed by epimeirsation to form the key trans-decalin framework. The route culminates in the stereoselective synthesis of an advanced tricyclic lactone intermediate, containing five contiguous sterogenic centres with the correct relative and absolute stereochemistry required for the anthracimycin core motif.

Discovery to Launch of Anti-allergy (Emadine; Patanol/Pataday/Pazeo) and Anti-glaucoma (Travatan; Simbrinza) Ocular Drugs, and Generation of Novel Pharmacological Tools Such as AL-8810

The eye and eyesight are exquistly designed and are precious, and yet we often take them for granted. Good vision is critical for our long-term survival and for humanity's enduring progress. Unfortunately, since ocular diseases do not culminate in life-and-death scenarios, awareness of the plight of millions of people suffering from such eye ailments is not publicized as other diseases. However, losing eyesight or falling victim to visual impairment is a frightening outlook for most people. Glaucoma, a collection of chronic optic neuropathies, of which the most prevalent form, primary open-angle glaucoma (POAG), is the second leading cause of irreversible blindness. POAG currently afflicts >70 million people worldwide and is an insidious, progressive, silent thief of sight that is asymptomatic. On the other hand, allergic conjunctivitis (AC), and the associated rhinitis ("hay-fever"), frequently victimizes a huge number of people worldwide, especially during seasonal changes. While not life-threatening, sufferers of AC soon learn the value of drugs to treat their signs and symptoms of AC as they desire rapid relief to overcome the ocular itching/pain, redness, and tearing AC causes. Herein, I will describe the collective efforts of many researchers whose industrious, diligent, and dedicated team work resulted in the discovery, biochemical/pharmacological characterization, development and eventual launch of drugs to treat AC (e.g., olopatadine [Patanol/Pataday/Pazeo] and emedastine [Emedine]), and for treating ocular hypertension and POAG (e.g., travoprost [Travatan ] and Simbrinza). This represents a personal perspective.

The Role of Trichloroacetimidate To Enable Iridium-Catalyzed Regio- and Enantioselective Allylic Fluorination: A Combined Experimental and Computational Study

Asymmetric allylic fluorination has proven to be a robust and efficient methodology with potential applications for the development of pharmaceuticals and practical synthesis for ¹⁸F-radiolabeling. A combined computational (dispersion-corrected DFT) and experimental approach was taken to interrogate the mechanism of the diene-ligated, iridium-catalyzed regio- and enantioselective allylic fluorination. Our group has shown that, in the presence of an iridium(I) catalyst and nucleophilic fluoride source (Et₃N·3HF), allylic trichloroacetimidates undergo rapid fluoride substitution to generate allylic fluoride products with excellent levels of branched-to-linear ratios. Mechanistic studies reveal the crucial role of the trichloroacetimidate as a potent leaving group and ligand to enable conversion of racemic allylic trichloroacetimidates to the corresponding enantioenriched allylic fluorides, via a dynamic kinetic asymmetric transformation (DYKAT), in the presence of the chiral bicyclo[3.3.0]octadiene-ligated iridium catalyst.

Iridium-Catalyzed Enantioselective Fluorination of Racemic, Secondary Allylic Trichloroacetimidates

The Ir-catalyzed enantioselective fluorination of racemic, branched allylic trichloroacetimidates with Et3N·3HF is a mild and efficient route for selective incorporation of fluoride ion into allylic systems. We herein describe the asymmetric fluorination of racemic, secondary allylic electrophiles with Et3N·3HF using a chiral-diene-ligated Ir complex. The methodology enables the formation of acyclic fluorine-containing compounds in good yields with excellent levels of asymmetric induction and overcomes the limitations previously associated with the enantioselective construction of secondary allylic fluorides bearing α-linear substituents.

Therapeutic uses of prostaglandin F(2α) analogues in ocular disease and novel synthetic strategies

The pharmacological management of glaucoma and ocular hypertension has significantly changed over the last 18 years with the introduction of PGF2α analogues, more specifically latanoprost (6), travoprost (8), bimatoprost (10) and tafluprost (12). Prostanoids are currently the first-line medicines among ocular antihypertensive drugs in terms of efficacy, safety, patient compliance and medical economy. Their ability to effectively reduce intraocular pressure with once-per-day dosing, ocular tolerability comparable to timolol and general lack of systemic adverse effects have made them the mainstay of pharmacological therapy for glaucoma and ocular hypertension all over the world. The present review reports a novel, convergent and highly diastereoselective method for the synthesis of PGF2α analogues from the structurally advanced prostaglandin phenylsulfone (5Z)-(+)-15 and new ω-chain synthons. The biochemistry, clinical efficacy and side effects of four commercially available PGF2α analogues, currently used as first-line agents for reducing intraocular pressure in patients with glaucoma or ocular hypertension, are also discussed.

Iridium-catalyzed allylic fluorination of trichloroacetimidates

A rapid allylic fluorination method utilizing trichloroacetimidates in conjunction with an iridium catalyst has been developed. The reaction is conducted at room temperature under ambient air and relies on Et(3)N·3HF reagent to provide branched allylic fluorides with complete regioselectivity. This high-yielding reaction can be conducted on a multigram scale and shows considerable functional group tolerance. The use of [(18)F]KF·Kryptofix allowed (18)F(-) incorporation in 10 min.