Applications in the Synthesis of Natural and Biologically Active Molecules

Sterically Tuned N-Heterocyclic Carbene Ligands for the Efficient Formation of Hindered Products in Ru-Catalyzed Olefin Metathesis

“…In comparison, the indenylidene analogue of the latter, complex Ru6 , 31 was visibly more productive in this transformation, however, providing still 5 percentage points lower conversion than the SIXyl complex ( Ru12 ). One can state that the improvement of 5 percentage points is not a significant difference, but in the history of olefin metathesis applied toward the synthesis of biologically active and natural products, 3 , 27 , 28 such a small difference noted for a simple model can often translate to much higher improvement in the case of real polyfunctional complex targets. 48 This was also the case here, as one can observe in scheme 4 – 6 later.…”

“… 25 Similar examples, where the application of sterically reduced NHC catalysts was for some reasons impossible or unprofitable and the standard SIMes catalysts were also suboptimal, 26 leading to low yields of the target products or requiring high catalyst loading have been published. 3 , 27 , 28 This problem is obviously even more serious in the context of larger-scale applications of the metathesis reaction in pharmaceutical production. 29 …”

Synthesis, Biological Profiling and Determination of the Tubulin-Bound Conformation of 12-Aza-Epothilones (Azathilones)

“…The former approach was elaborated for scale-up purposes in response to difficulties that had been encountered for the reduction of the 9,10 double bond formed in the ring-closing step. In spite of these difficulties, our synthesis of quinoline-based azathilones 3 and 4 was to rely on RCM-based macrocyclization, simply because this approach would also provide simultaneous access to the desired 9,10-dehydro analogs 5 and 6 [28]. We also felt that a sufficient investment in the optimization of the reduction step after RCM would eventually allow us to perform the reaction in satisfactory yield.…”

Editorial of Special Issue Ruthenium Complex: The Expanding Chemistry of the Ruthenium Complexes

“…Ru-catalyzed enyne metathesis (EYRCM) provided an elegant and productive way to obtain small, medium and large cyclic molecules [255]. Numerous tandem metathesis protocols (RCM-CM, RCM-RCM, and RCM-ROM-CM), as well as related processes (C–C coupling, cyclopropanation, cyclizations, and polymerizations) facilitated the synthesis of complex organic molecules, intermediates for fine chemicals, bioactive natural products, macrocyclic or polycyclic structures, functional polymers and supramolecular architectures [256,257,258,259,260,261,262,263,264]. Intricate scaffolds for pharmaceuticals and agrochemicals have been accessed by these advanced strategies [265,266,267].…”

“…Intricate scaffolds for pharmaceuticals and agrochemicals have been accessed by these advanced strategies [265,266,267]. In a short time total syntheses, involving key metathesis steps (mostly RCM or EYRCM) were competitively advanced by different groups, providing an elegant and easier access to a plethora of complex bioactive molecules that display antitumor, antiviral, anti-HIV, antimicrobial, antifungal activities, and also to alkaloids and other classes of naturally occurring compounds [260,261,268]. More particular cases like metathesis-based syntheses of a range of iminosugars, and bioactive iriomoteolide and kendomycin were given special attention [269,270,271,272,273].…”