I'd originally planned to do four of these posts, but it looks like I've run out of time so I'll be getting back to more cutting edge work (as soon as something exciting is published). Maybe I'll post the last one in
March Mulch. Check out Mulvember 1: Penfulvin A and Mulvember 2: Echinopines A and B!
Okay, I suppose I should start off by acknowledging that Mulzer isn't the corresponding author on this one (instead it's Mulzer group postdoc Jürgen Ramharter), but it's still a nice piece of work so I'm including it anyway. The target itself is one of the perennially popular lycopodium alkaloids whose first member - lycopodium itself - was isolated way back in 1881. A number of classic syntheses of members of this family in the 1970s and 80s by famous alkaloid chemists such as Stork, Heathcock, Wiesner and Wenkert have set the bar pretty high, but work towards these targets continues to this day. Particularly, the fawcettimine-type members of this family, to which lycoflexine belongs, have proved very popular in recent years with a new synthesis seemingly out every few months.
Although there have been a couple of interesting syntheses this week, I'm still very busy so I'm going to write about another Mulzer synthesis from my talk. See my previous post for the background to this tribute.
Since their fairly recent isolation in 2008 the echinopine sesquiterpenes have proved quite popular targets for total synthesis. In fact, four rather different total syntheses have been reported since their unusual and compact molecular architectures first graced the literature. The first of these was that of Johann Mulzer, published just a year after their isolation, in which both natural products were synthesised in near enantiopure form (starting from cyclooctadiene!) and their absolute configurations were confirmed for the first time.
Like many research groups, the one I’m in does weekly literature talks so people get a bit of practice with powerpoint and public speaking. Because excessive freedom can be a bit daunting, although people are free to choose the topic of their own talk it has to fit in with a particular theme, which, at the moment, is living Germanic chemists. In this vein, last month I wrote and gave a talk on the life and work of Johann Mulzer. Now, as I've been a bit busy lately, and the literature has been a bit lacking in interesting total syntheses, I've decided to rehash my talk as a series of blog posts. On the upside, this should mean more posts for you guys and less hassle for me (as I've already drawn everything in ChemDraw). Also, although I didn't know this when I wrote the talk, it seems that Mulzer is finally winding down and I think he deserves a bit of send-off. I, for one, have learnt a lot from reading his papers over the past few years.
From a recent Angewandte paper.
Unfortunately, most of the syntheses that I covered in my talk are already pretty well known, and many of them have also already been covered on Totally Synthetic at one time or other. Still, if you missed somehow missed reading about them there or prefer my more rambling style then read on!
Incidentally, if you’re wondering what the German text on the slide is all about, it’s taken from the group website and is usually rendered (non-literally) in English as ‘no battle plan survives contact with the enemy’, something all chemists who have worked in total synthesis know well!