9. Mechanism Monday – The Endgame of Overman’s Total Synthesis of Actinophyllic Acid

Well, this is what I consider a classic. I have proposed it a couple of times in group meetings and it has never ceased to amaze me.

This, Ladies and Gentlemen, is what I call a spectacular endgame! Four reactions for the price of one!

Have a close look at it, give it a try, and get back to the original paper once you have found a satisfactory mechanism.

9Reference: J. Am. Chem. Soc. 2010 4894-4906 link

8. Mechanism Monday: the Gold-catalysed spiroannulation of enynes and cyclopropenones by Matsuda et al.

Though the field is not that new and was explored in much details by many, I still find gold catalysis has a strong appeal. A good reason for this is that I have found gold-catalysed reactions to occur following an original mechanism that would seem queer in other Lewis-acid or transition-metal-catalysed reactions.

The following reaction between an enyne and a cyclopropenone was reported earlier this year by Matsuda and Sakurai from the Tokyo University of Science. Trying to find the mechanism is trickier than it looks at first and I found it to be a good exercise on gold catalysis .

8.a

Reference :

J. Org. Chem. 2014, 2739-45. link