Erysodienone is a key precursor in the

biosynthesis Biosynthesis, i.e., chemical synthesis occurring in biological contexts, is a term most often referring to multi-step, enzyme-Catalysis, catalyzed processes where chemical substances absorbed as nutrients (or previously converted through biosynthe ...

of many ''

Erythrina ''Erythrina'' is a genus of plants in the pea family, Fabaceae. It contains about 130 species, which are distributed in tropical and subtropical regions worldwide. They are trees, with the larger species growing up to in height. These species ...

''-produced

alkaloids Alkaloids are a broad class of naturally occurring organic compounds that contain at least one nitrogen atom. Some synthetic compounds of similar structure may also be termed alkaloids. Alkaloids are produced by a large variety of organisms i ...

. Early work was done by

Derek Barton Sir Derek Harold Richard Barton (8 September 1918 – 16 March 1998) was an English organic chemist and Nobel Prize laureate for 1969. Education and early life Barton was born in Gravesend, Kent, to William Thomas and Maude Henrietta Barton ...

and co-workers to illustrate the

biosynthetic pathway In biochemistry, a metabolic pathway is a linked series of chemical reactions occurring within a cell. The reactants, products, and intermediates of an enzymatic reaction are known as metabolites, which are modified by a sequence of chemical re ...

s towards erythrina alkaloids. It was demonstrated that erysodienone could be synthesized from simple starting materials by a similar approach as its biosynthetic pathway, which led to the development of the biomimetic synthesis of erysodienone.

Synthesis

The biosynthesis of erysodienone involves a key step of

oxidative Redox ( , , reduction–oxidation or oxidation–reduction) is a type of chemical reaction in which the oxidation states of the reactants change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is ...

phenol Phenol (also known as carbolic acid, phenolic acid, or benzenol) is an aromatic organic compound with the molecular formula . It is a white crystalline solid that is volatile and can catch fire. The molecule consists of a phenyl group () ...

coupling. Starting with S-norprotosinomenine precursor A,

cyclization A cyclic compound (or ring compound) is a term for a compound in the field of chemistry in which one or more series of atoms in the compound is connected to form a ring. Rings may vary in size from three to many atoms, and include examples where ...

via oxidative phenol coupling forms intermediate B, which in turn can be rearranged to form intermediate C.

Hydrogenation Hydrogenation is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst such as nickel, palladium or platinum. The process is commonly employed to redox, reduce or Saturated ...

of C forms the diphenoquinone intermediate E. An intramolecular

Michael addition In organic chemistry, the Michael reaction or Michael 1,4 addition is a reaction between a Michael donor (an enolate or other nucleophile) and a Michael acceptor (usually an α,β-unsaturated carbonyl) to produce a Michael adduct by creating a c ...

reaction converts E to the final product, erysodienone. : Structure of erysodienone and its proposed biosynthetic pathway

A biomimetic synthesis route for erysodienone was developed based on a similar oxidative phenol coupling mechanism. Barton and co-workers found that treating bisphenolethylamine precursor F with oxidants such as

K3Fe(CN)6 Potassium ferricyanide is the chemical compound with the formula K3 e(CN)6 This bright red salt contains the octahedrally coordinated 3−">e(CN)6sup>3− ion. It is soluble in water and its solution shows some green-yellow fluorescence. It ...

initiated oxidative phenol coupling to form the 9-membered ring structure in intermediate D that itself undergo a Michael addition to give erysodienone. : Biomimetic synthesis of erysodienone

Synthesis

References

Further reading