Five-membered heterocyclic arenes account for a large portion of the heterocycles found in pharmaceuticals and bioactive molecules.1 Synthesis of heteroaryl halides and elaboration via metal catalysed cross coupling reactions- particularly with aliphatic amines- is, however, known to be challenging. These small heterocycles-particularly electron-rich systems- frequently coordinate to palladium, promoting catalyst deactivation via displacement of the supporting

The scheme below shows the synthesis of a late-stage intermediate towards PF-06826647, a compound identified by Pfizer as a potent and selective tyrosine kinase 2 (TYK-2) inhibitor that has entered phase 2 clinical trials for the treatment of autoimmune diseases. Can you identify intermediates A, B and D? Answers and a reference will be posted

A couple of interesting papers published recently on aryl iodination. I sure I don’t need to reiterate how useful iodinated intermediates are in synthesis- most significantly their heightened reactivity in metal catalysed cross coupling chemistry,1 and, more recently their application as organocatalysts in hypervalent iodine chemistry.2 As is common in synthetic science, the intermediates you

The scheme below shows the synthesis of a late-stage intermediate towards AZD9833, a compound identified by AstraZeneca as a selective estrogen receptor degrader (SERD) and antagonist that is currently in phase 2b clinical trials for the treatment of ER+ breast cancer. Can you identify reagents or intermediates A, B and C? Answers and a reference

Last month I posted a scheme from showing Oppolzer’s synthesis of racemic Lysergic acid and asked if you could identify reagents or intermediates G, I, and H. Below are the answers! You can read more here in the full reference: W. Oppolzer et al, Helv. Chim. Acta 1981, 64, 478–481  

In 1981 Oppolzer published a short, racemic synthesis of Lysergic acid. Below is a scheme of the early steps in the synthesis. Can you identify reagents or intermediates G, I and H? Answers and a reference will be posted in late June, along with another problem. Enjoy!  

Last month I posted a scheme from a paper by a team from Merck describing the synthesis of a soluble guanylate cyclase (cGC) stimulator of interest for the treatment of hypertension and asked if you could identify reagents or intermediates B, F, and the target compound H. Below are the answers! You can read more here in

A recent paper by a team from Merck describe the synthesis of a soluble guanylate cyclase (cGC) stimulator of interest for the treatment of hypertension. Can you identify reagents or intermediates B, F and the target compound H? Answers and a reference will be posted in May, along with another problem. Enjoy!

Last month I posted a scheme from a paper by Jonathan H. George et al at the University of Adelaide describing a biomimetic total synthesis of the Rhododendron meroterpenoids rubiginosins A and G and asked if you could identify reagents or intermediates B, D, E and H. Below are the answers! You can read more here

Any new synthetic methodology, as well as advancing the state of the art, should also consider a few other key criteria, one of which is to build complexity from common feedstock materials- ideally using cheap and environmentally friendly reagents and raw materials. Unactivated (or unsubstituted) olefins, used largely by the polymer industry, represent a rich