Morita-Baylis-Hillman Approach toward Formal Total Synthesis of Tamiflu and Total Synthesis of Gabaculine

Morita-Baylis-Hillman adducts and their derivatives: a patent-based exploration of diverse biological activities

Morita-Baylis-Hillman adducts are polyfunctionalized compounds that result from a three-component reaction involving an electrophilic sp2 carbon (aldehyde, ketone or imine) and the α-position of an activated alkene, catalyzed by a tertiary amine. These adducts exhibit a wide range of biological activities and act as valuable starting materials for developing drug candidates, pesticides, polymers, and other applications. In this regard, the present review aimed to explore the biological potential of Morita-Baylis-Hillman adducts and their derivatives as documented in patent literature. Additionally, the review delves into the synthetic methodologies employed in their preparation.

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.

The evolution of Tamiflu synthesis, 20 years on: Advent of enabling technologies the last piece of the puzzle?

Influenza is a serious respiratory disease responsible for significant morbidity and mortality due to both annual epidemics and pandemics; its treatment involves the use of neuraminidase inhibitors. (-)-Oseltamivir phosphate (Tamiflu) approved in 1999, is one of the most potent oral anti-influenza neuraminidase inhibitors. Consequently, more than 70 Tamiflu synthetic procedures have been developed to date. Herein, we highlight the evolution of Tamiflu synthesis since its discovery over 20 years ago in the quest for a truly efficient, safe, cost-effective and environmentally benign synthetic procedure. We have selected a few representative routes to give a clear account of the past, present and the future with the advent of enabling technologies.

Enantioselective Michael Reaction of Cyclic β-Ketoesters with Morita-Baylis-Hillman Derivatives Using a Phase-Transfer Catalyst

This study aims to develop a highly enantioselective Michael reaction of cyclic β-ketoesters with Morita-Baylis-Hillman (MBH) derivatives using a phase-transfer catalyst. Cyclic β-ketoesters reacted with MBH derivatives to stereoselectively generate a quaternary carbon center in the presence of cinchona alkaloid-derived bulky ammonium catalyst, and aqueous KOH and Michael adducts bearing an acrylate moiety were obtained in good chemical yields with good enantioselectivity.

A computational investigation of the solvent-dependent enantioselective intramolecular Morita–Baylis–Hillman reaction of enones

A DFT study of the enantioselective organocatalytic intramolecular Morita–Baylis–Hillman (IMBH) reaction of enones under the influence of 1,1,1,3,3,3-hexafluoroisopropanol is reported. This study establishes an excellent fit between the experiment and theory.

An enantioselective organocatalytic intramolecular Morita–Baylis–Hillman (IMBH) reaction of dienones, and elaboration of the IMBH adducts to fluorenones

An efficient synthesis of cyclopenta-fused arenes and heteroarenes has been achieved via an enantioselective organocatalytic intramolecular Morita–Baylis–Hillman (IMBH) reaction of dienones. The IMBH-adducts were transformed to fluorenones in a serendipitous manner.

Morita-Baylis-Hillman Reaction of β,β-Disubstituted Enones: An Enantioselective Organocatalytic Approach for the Synthesis of Cyclopenta[b]annulated Arenes and Heteroarenes

The first enantioselective organocatalytic intramolecular Morita-Baylis-Hillman (MBH) reaction of sterically highly demanding β,β-disubstituted enones is presented. The MBH reaction of β,β-disubstituted-α,β-unsaturated electron-withdrawing systems was previously considered to be unfeasible. Towards this end, designer substrates, which under simple and practical reaction conditions generate a variety of cyclopenta[b]annulated arenes and heteroarenes in excellent enantiopurities and near-quantitative yields in remarkably short reaction times, are described. The reason for the unusually facile nature of this reaction is attributed to the synergy guided and entropically favored intramolecular reaction. Further, this strategy provides easy access to a substantial number of bioactive natural products and pharmaceutically significant compounds.

Synthesis of fully protected, reverse N-prenylated (2S,3R)-3-hydroxytryptophan, a unique building block of the cyclomarins

The rather exotic amino acid of the cyclomarins, is obtained in enantio- and diastereomerically pure and fully protected form.

Intramolecular Morita–Baylis–Hillman and Rauhut–Currier reactions. A catalytic and atom economic route for carbocycles and heterocycles

Intramolecular MBH and RC reactions: glorious past and future opportunities.