Metathesis Reactions in Natural Product Fragments and Total Syntheses

Abstract

The passion of total‐ and fragments syntheses of natural products always remained one of the top priorities among the synthetic chemists worldwide. Due their curiosity toward the complexity of molecules of living nature and their endeavour to imitate them in laboratory; limitless arrays of natural products have been extracted, architecturally‐elucidated, synthesized, and chronicled by utilizing various synthetic methodologies in different fashions. Frequently, the synthesis of complex natural products proceed with inscrutable synthetic challenges, which can be circumvented either by modification of previously developed synthetic methods or by formulating a new one. In this way, a myriad of powerful synthetic reactions have been developed since the genesis of the logic of chemical synthesis. Amongst them, metathesis tactics discovered unexpectedly in the 1950s (Nobel Prize in 2005), have incredibly influenced and changed the landscape of the art of the total and formal synthesis in the last three A. H. Hoveyda, A. R. Zhugralin, me abruptly as compared to other developed transformations or their modified forms. In this particular review article, we envisioned to report a comprehensive detail of the metathetic tools involved in both total and fragments synthesis of natural products in the years 2018 and 2019 along with an overview of 2017.

Collective total syntheses of cytochalasans and merocytochalasans

“…With the 5/6 bicyclic ring system secured, we moved to construct the 11-membered macrocyclic ring through RCM reaction (Scheme 6). To our delight, upon the treatment of 37 with the Grubb's II catalyst, the expected reaction works smoothly, giving rise to tricyclic compound 22a in an excellent yield [46,47]. Interestingly, the RCM reaction displays remarkable E/Z selectivity, only resulting in (E)-isomer 22a.…”

Catalytic Olefin-Imine Metathesis: Cobalt-Enabled Amidine Olefination with Enaminones

“…[1][2][3][4][5] In this regard, the classic olefin-olefin metathesis has demonstrated its powerful utility in organic synthesis, drug discovery, and materials engineering. [6][7][8][9][10][11][12] The stepwise cycloaddition/cycloreversion Chauvin mechanism typically entails the participation of a transition metal alkylidene complex as the catalyst. 13 Olefincarbonyl metathesis has recently emerged as an alternative mechanistic framework for expanding synthetic design into the heteroatom regime.…”

Dithieno[3,2-b:2′,3′-d]thiophene (DTT): an emerging heterocyclic building block for future organic electronic materials & functional supramolecular chemistry

“… 1 Generally, heterocyclic compounds are vital molecules as they play a significant role in biochemical fields, pharmaceutical, organic electronics, medicinal chemistry and also in the material sciences and technology etc. 2–16 The five membered doubly unsaturated cyclopentadiene system is a non-aromatic, whereas the five membered heterocyclic systems viz. furan, pyrrole and thiophene having oxygen, nitrogen and sulfur, respectively are aromatic in nature as the lone pair present on the heteroatom (in unhybridized p-orbital) in these systems participate in conjugation, thereby resulting in the Huckel's aromaticity (cyclic, planar, conjugated, & (4 n + 2)π electrons).…”