A novel approach to the aspidosperma family of alkaloids was developed and applied to a concise total synthesis of pseudotabersonine that was accomplished in 11 steps. Metathesis in natural product synthesis johnson matthey. Since the stereogenic centers were directly derived from the amino acids, the current synthetic route has further supported the absolute stereochemistry revision by lindsley. Furthermore, rcm is becoming the most popular way to construct large rings and has the advantage of. Janine cossy, stellios arseniyadis, christophe meyer, robert h. A concise total synthesis of dactylol via ring closing metathesis. Ring closing metathesis rcm the ringclosing metathesis rcm allows synthesis of 5 up to 30membered cyclic alkenes. His research interests mainly focus on the total synthesis of natural products. Control of olefin geometry in macrocyclic ringclosing metathesis using a removable silyl group.
The rucatalysts used tolerate a variety of functional groups, but normally the molecule must have polar side chains that are able to build a template for the catalyst. This paper is dedicated to the memory of professor alan r. The synthesis of polycyclic ethers with variable ring sizes can be conducted by twodirectional double ringclosing metathesis. The ring closing metathesis rcm of dienes is probably the most exploited metathesis. Handbook of metathesis, volume 2 and millions of other books are available for amazon kindle. Fr900482 1 has been completed using an approach that featured the. The total synthesis of ciguatoxin ctx3c is an impressive example featuring multiple uses of rcm reactions including the formation of several medium sized rings. New commercial and academic applications can be envisioned and the number of total synthesis of natural products based on these methodologies increases. The key step of the enantioselective total synthesis of terreumol c is a ringclosing metathesis to form a trisubstituted z double bond embedded in the 10membered ring of the 8. In recent years, ring closing metathesis rcm has become one of the most paramount tools in synthetic organic chemistry especially in the field of total synthesis of macrolide natural products, 30, 31. One example is its use in the formation of the 12membered ring in the synthesis of the naturally occurring cyclophane floresolide. Floresolide b was isolated from an ascidian of the genus apidium and showed cytotoxicity against kb tumor cells. Ring closing metathesis an overview sciencedirect topics. Application of ringclosing metathesis to the formal total synthesis.
The key bondforming reactions in this approach are a chemoselective cross metathesis cm and rcm. Strategies, substrates and catalysts 9783527324408. Ringclosing metathesis is important in total synthesis. Total synthesis of patulolide a through ring closing metathesis.
Olefin metathesis reactions in total synthesis all things metathesis. This methodology was used to prepare, in onestep, the tricyclic ether 73, which has a six, seven, and eightmembered ring scheme 9. Key transformations include a stepwise variant of a mannichlike multicomponent assembly process, a double ring closing metathesis sequence, and a onepot deprotection. Metathesis definition of metathesis by medical dictionary. Ringclosing metathesis, or rcm, is a widely used variation of olefin metathesis in organic chemistry for the synthesis of various unsaturated rings via the.
Rutheniumbased ringclosing metathesis in synthesis of swainsonine and castanospermine. In summary, a convergent total synthesis of the revised structure of ciliatamides a and b via protecting group directed ring closing metathesis reaction has been described. Metathesis definition of metathesis by the free dictionary. Rutheniumcatalyzed olefin cross metathesis ring closing metathesis, rcm between terminal alkenes and vinylboronic acid or esters has recently been developed for the synthesis of e1alkenylboron compounds from alkenes.