: The unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio. Harmonic force fields are obtained using Density Functional Theory (DFT), MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set. DFT calculations use the Local Spin Density Approximation (LSDA), BLYP, and Becke3LYP (B3LYP) density functionals. Mid-IR spectra predicted using LSDA, BLYP, and B3LYP force fields are of significantly different quality, the B3LYP force field yielding spectra in clearly superior, and overall excellent, agreement with experiment. The MP2 force field yields spectra in slightly worse agreement with experiment than the B3LYP force field. The SCF force field yields spectra in poor agreement with experiment.The basis set dependence of B3LYP force fields is also explored: the 6-31G* and TZ2P basis sets give very similar results while the 3-21G basis set yields spectra in substantially worse agreements with experiment. jg

Ab initio calculation of vibrational absorption and circular dichroism spectra using density functional force fields

The organometallic approach is one of the most active topics in catalysis. The application of NH functionality in organometallic catalysis has become an important and attractive concept in catalyst design. NH moieties in the modifiers of organometallic ca

The N-H functional group in organometallic catalysis.

Reductive amination plays a paramount role in pharmaceutical and medicinal chemistry owing to its synthetic merits and the ubiquitous presence of amines among biologically active compounds. It is one of the key approaches to C-N bond construction due to its operational easiness and a wide toolbox of protocols. Recent studies show that at least a quarter of C-N bond-forming reactions in the pharmaceutical industry are performed via reductive amination. This Review concisely compiles information on 71 medical substances that are synthesized by reductive amination. Compounds are grouped according to the principle of action, which includes drugs affecting the central nervous system, drugs affecting the cardiovascular system, anticancer drugs, antibiotics, antiviral and antifungal medicines, drugs affecting the urinary system, drugs affecting the respiratory system, antidiabetic medications, drugs affecting the gastrointestinal tract, and drugs regulating metabolic processes. A general synthetic scheme is provided for each compound, and the description is focused on reductive amination steps. The green chemistry metric of reaction mass efficiency was calculated for all reactions.

Reductive Amination in the Synthesis of Pharmaceuticals.

Asymmetric hydrogenation plays an important role in organic synthesis, but that of the challenging substrates such as N-unprotected imines, enamines, and N-heteroaromatic compounds (1H-indoles, 1H-pyrroles, pyridines, quinolines, and quinoxalines) has only received increased attention in the past three years. Considering the interaction modes of a Bronsted acid with a Lewis base, Bronsted acids may be used as the ideal activators of C=N bonds. This Minireview summarizes the recent advances in transition-metal-catalyzed, Bronsted acid activated asymmetric hydrogenation of these challenging substrates, thus offering a promising substrate activation strategy for transformations involving C=N bonds.

Brønsted acid activation strategy in transition-metal catalyzed asymmetric hydrogenation of N-unprotected imines, enamines, and N-heteroaromatic compounds.

https://tspace.library.utoronto.ca/bitstream/1807/98861/1/SeoMorrisForOrganometallics.pdf

Catalytic Homogeneous Asymmetric Hydrogenation: Successes and Opportunities

The first example of an intramolecular asymmetric reductive amination of a dialkyl ketone with an aliphatic amine has been developed for the synthesis of Suvorexant (MK-4305), a potent dual Orexin antagonist under development for the treatment of sleep disorders. This challenging transformation is mediated by a novel Ru-based transfer hydrogenation catalyst that provides the desired diazepane ring in 97% yield and 94.5% ee. Mechanistic studies have revealed that CO2, produced as a necessary byproduct of this transfer hydrogenation reaction, has pronounced effects on the efficiency of the Ru catalyst, the form of the amine product, and the kinetics of the transformation. A simple kinetic model explains how product inhibition by CO2 leads to overall first-order kinetics, but yields an apparent zero-order dependence on initial substrate concentration. The deleterious effects of CO2 on reaction rates and product isolation can be overcome by purging CO2 from the system. Moreover, the rate of ketone hydrogenati...

Reaction development and mechanistic study of a ruthenium catalyzed intramolecular asymmetric reductive amination en route to the dual Orexin inhibitor Suvorexant (MK-4305).

The present invention is directed to processes for preparing a diazepane compound which is an antagonist of orexin receptors, and which is useful in the treatment or prevention of neurological and psychiatric disorders and diseases in which orexin receptors are involved. The present invention is further directed to crystalline forms of this diazepane compound and pharmaceutical compositions thereof.

Process for the preparation of an orexin receptor antagonist

An efficient route to the HCV antiviral agent uprifosbuvir was developed in 5 steps from readily available uridine in 50% overall yield. This concise synthesis was achieved by development of several synthetic methods: (1) complexation-driven selective acyl migration/oxidation; (2) BSA-mediated cyclization to anhydrouridine; (3) hydrochlorination using FeCl3/TMDSO; (4) dynamic stereoselective phosphoramidation using a chiral nucleophilic catalyst. The new route improves the yield of uprifosbuvir 50-fold over the previous manufacturing process and expands the tool set available for synthesis of antiviral nucleotides.

/pdf/efficient-synthesis-of-antiviral-agent-uprifosbuvir-enabled-2d9x6o94yj.pdf

Timothy J. Wright

Papers

Reaction development and mechanistic study of a ruthenium catalyzed intramolecular asymmetric reductive amination en route to the dual Orexin inhibitor Suvorexant (MK-4305).

Process for the preparation of an orexin receptor antagonist

Efficient synthesis of antiviral agent uprifosbuvir enabled by new synthetic methods

Manufacturing Process Development for Belzutifan, Part 6: Ensuring Scalability for a Deoxyfluorination Reaction

Kilogram-Scale Synthesis of 2′-C-Methyl-arabino-Uridine from Uridine via Dynamic Selective Dipivaloylation