Stereodivergent synthesis of all the four stereoisomers of antidepressant reboxetine

Synthesis of anti-depressant molecules via metal-catalyzed reactions: a review

Depression is one of the most mutilating conditions in the world today. It has been difficult to make advancements toward better, more effective therapies since the introduction of antidepressant medicines in the late 1950s. One important field of medicinal chemistry is the synthesis of antidepressant molecules through metal-catalyzed procedures. The important role that different transition metals, including iron, nickel, ruthenium, and others, serve as catalysts in the synthesis of antidepressants is examined in this review. Key structural motifs included in antidepressant drugs such as tricyclic antidepressants (TCAs), selective serotonin reuptake inhibitors (SSRIs), and others can be synthesized in a variety of effective ways using metal-catalyzed steps. This review examines current developments in the catalytic synthesis of antidepressants and their potential application over the previous thirteen years.

A Unified Strategy for the Asymmetric Synthesis of Highly Substituted 1,2-Amino Alcohols Leading to Highly Substituted Bisoxazoline Ligands

A general procedure for the asymmetric synthesis of highly substituted 1,2-amino alcohols in high yield and diastereoselectivity is described that uses organometallic additions of a wide range of nucleophiles to tert-butylsulfinimines as the key step. The addition of organolithium reagents to these imines follows a modified Davis model. The diastereoselectivity for this reaction depends significantly on both the nucleophile and electrophile. These highly substituted 1,2-amino alcohols are used to synthesize stereochemically diverse and structurally novel, polysubstituted 2,2'-methylene(bisoxazoline) ligands in high yields.

Epoxide Syntheses and Ring-Opening Reactions in Drug Development

This review concentrates on success stories from the synthesis of approved medicines and drug candidates using epoxide chemistry in the development of robust and efficient syntheses at large scale. The focus is on those parts of each synthesis related to the substrate-controlled/diastereoselective and catalytic asymmetric synthesis of epoxide intermediates and their subsequent ring-opening reactions with various nucleophiles. These are described in the form of case studies of high profile pharmaceuticals spanning a diverse range of indications and molecular scaffolds such as heterocycles, terpenes, steroids, peptidomimetics, alkaloids and main stream small molecules. Representative examples include, but are not limited to the antihypertensive diltiazem, the antidepressant reboxetine, the HIV protease inhibitors atazanavir and indinavir, efinaconazole and related triazole antifungals, tasimelteon for sleep disorders, the anticancer agent carfilzomib, the anticoagulant rivaroxaban the antibiotic linezolid and the antiviral oseltamivir. Emphasis is given on aspects of catalytic asymmetric epoxidation employing metals with chiral ligands particularly with the Sharpless and Jacobsen–Katsuki methods as well as organocatalysts such as the chiral ketones of Shi and Yang, Pages’s chiral iminium salts and typical chiral phase transfer agents.

Stereodivergent, Chemoenzymatic Synthesis of Azaphilone Natural Products

Selective access to a targeted isomer is often critical in the synthesis of biologically active molecules. Whereas small-molecule reagents and catalysts often act with anticipated site- and stereoselectivity, this predictability does not extend to enzymes. Further, the lack of access to catalysts that provide complementary selectivity creates a challenge in the application of biocatalysis in synthesis. Here, we report an approach for accessing biocatalysts with complementary selectivity that is orthogonal to protein engineering. Through the use of a sequence similarity network (SSN), a number of sequences were selected, and the corresponding biocatalysts were evaluated for reactivity and selectivity. With a number of biocatalysts identified that operate with complementary site- and stereoselectivity, these catalysts were employed in the stereodivergent, chemoenzymatic synthesis of azaphilone natural products. Specifically, the first syntheses of trichoflectin, deflectin-1a, and lunatoic acid A were achieved. In addition, chemoenzymatic syntheses of these azaphilones supplied enantioenriched material for reassignment of the absolute configuration of trichoflectin and deflectin-1a based on optical rotation, CD spectra, and X-ray crystallography.