| Synthetic Remarks |
| The World through the Eyes of an Organic Chemist |
| http://syntheticremarks.com |
| Name A and B! |
| Here is a one-step transformation that I think few, perhaps not even Corey,* would come up with upon a traditional retrosynthetic analysis. A and B are everyday organic reagents. The solvent is DCM and the temperature is around 0 °C. No metals, complexes or weird oxidation level crap. So – go ahead and name A and B! Remember I have this Stuxnet 3.5 beta spyware installed on all of your computers that smell out and report the use of SciFinder and Reaxys. Likewise through your webcam, Vogel, March, Paquette and Larock are detected, to name a few. Kudos to FA, my fellow grad student, who back in the days included this example in his thesis (also recognized by my software). * Retract that. Corey would have. |
| ** LINK ** |
| My new friend |
| I have a new BFF. Meet this mother of an ate-complex: Recipe inhere: J. Org. Chem. 2007, 72, 5113-5118. (DOI: 10.1021/jo070643y) The structure looks scary, but its preparation is quite straightforward, actually. My new friend was able to ortho-lithiate an ‘impossible’ starting material and allowed me to introduce an electophile in a pretty weird position, in the presence of pretty labile functional groups. On a several gram scale and with a good isolated yield too. Yeah, t-Bu2(LiTMP)Zn is officially a dear friend of me, alright. Try her too if you get the chance! She’s now up there with Oshima’s magic ate-complexes, Schlosser’s superbases and Knochel’s Turbo-Grignards. Peace out. |
| ** LINK ** |
| Help me nail this Sonogashira |
| Help! I have this stubborn starting material that is quite reluctant to react the way I need it to, under typical Sonogashira conditions with propargyl alcohol (PdCl2(PPh3)2, CuI, pyrrolidine, heat). I am unfortunately not at liberty to disclose the exact structure, but what I can say is that the arylbromide is quite electron-rich (FGs = several e-donating groups, R = alkyl chain). The corresponding aryliodide does unfortunately not exist and would be pretty demanding to synthesize, so that is not really an option. The molecule also contains a silyl protection group, but that should not matter. What conditions might get the desired reaction going? I now see a very slow conversion of the starting material over several days, and the isolated yield of the desired product is below 10 %. There is an annoying side-reaction too, which is not plain reduction, that consumes most of the arylbromide. I am counting on your cross-coupling expertise here! Any obvious quick-fix? I should also say that this is on gram scale, so glove box-ish conditions are not acceptable. Do you think an NHC palladium catalyst would perform better? If so, which one? Conditions? The catalyst/ligand has to be commercial. Please include Sigma-Aldrich item numbers and/or DOIs Thank you! |
| ** LINK ** |
| Cleaning up |
| Spring was in the air today. Serious tidying up was in place. Unlabeled samples were trashed. Flasks, bottles and retorts were subjected to all kinds of solvents, then dried under the sun. Cobwebs were torched. At the end of the day, I even arsed myself to install electric lighting. Yes, I find it so much easier to start a new experiment when everything is neat and tidy. |
| ** LINK ** |
| Beware of upside-down fish |
| After unpacking today’s deliveries, one bottle stood out. The upside-down fish is creepy as hell. Also, I love the other GHS symbol that says ‘no GHS symbol’ – akin to the liar paradox – poetic almost. So… what do you think this could be? Hint: It is not fentanyl, sarin, Botulinum toxin or plutonium. Nah, this badass mofo is a chief compontent in for instance deodorant and dental cement. Google CAS# 7646-85-7 if you fail to figure it out. |
| ** LINK ** |
| Wait for it |
| The plan is to resurrect here in a couple of weeks from now. Until then, I am crazy busy. See you on the other side. |
| ** LINK ** |
| Gyro Gearloose |
| Let me tell you about my daily encounter with Gyro Gearloose. The web interface I use to access the literature accepts most of the common abbreviation we use without a glitch. For instance, if I type JACS, the first and only hit is the Journal of the American Chemical Society. Same thing with JOC – until just recently. For the past few weeks, the Journal of Organic Chemistry has slipped down to the second row. Look: This is in Swedish, but row three’s “Oppfinnar-Jockes kluriga magasin” would be “The ingenious magazine of Gyro Gearloose” (my translation). This totally makes me smile every single time. Who is responsible for subscribing to this journal from 1982 until present day? (Which you find out if you follow the link – unfortunately, there are no pdf:s and no DOI:s). Finally, if you could shed some light on what type of literature “Sober Yet Jocular Answer to Heraclitus Ridens” might be, row four, I am all ears. |
| ** LINK ** |
| What’s the mechanism? |
| Time for another short quiz! This one is a little tougher than the last one, I believe. What is the mechanism for the following transformation? And hey, no looking in SciFinder, Reaxys, Wikipedia, books or the literature. Only pencil, paper and brains are allowed. The first one to submit the correct answer down below will get a nice prize sent to him or her in the physical world. Go! |
| ** LINK ** |
| Organic solar cells (video) |
| This brief introduction to organic solar cells, and their potential for a very bright future (cheesy – I know), recently surfaced on Vimeo. I like it. More scientists should go out and make short and snappy video clips about their research and post it online for all to see. And yeah, I will be returning to organoelectronics for some time to come now, if you don’t mind. In a foreseeable future, if you are still with me, you will see why and everything will make sense. “PhD Candidate Graham Morse, working with Professor Tim Bender, has created a new organic chemical compound that has bipolar electrochemical properties. Called Phthalimido-boronsubphthalocyanines, this new material is critical to the development of organic solar cells.” Bender’s group page is over here. Thank you! |
| ** LINK ** |
| Are those nanoputians, Olah? |
| When I first saw compounds 22 and 23 (reference in Figure 2), I associated them with hieroglyphs, but as I carried on they struck me more as typical results of draw-a-person tests that they give four-year-olds (Figure 1). Figure 1. a) Hieroglyphs b) Combined head and body, age 4½ Upon reading and re-reading this paper, however, I have finally come to the conclusion that 22 and 23 must be classified as nanoputians, see JOC 2003, 68, 8750–8766. (DOI: 10.1021/jo0349227) Or, shall we say fluoro-nanoputians? First of their kind. I love them! Nice one, Olah. Figure 2. From Org. Lett., Article ASAP (DOI: 10.1021/ol300076y) Figure 3. In my head. Seriously, I like this paper a lot. I have no idea why we need trifluoromethyl-styrenes – yet, but I am sure that we can think of something – eventually. If that came out condescending, you misunderstand me completely. I am very much in favor of this way of conducting science: We work hard and we uncover new things. Most of the time, we have no idea what our discoveries could be used for. This worked for Einstein. Yeah, this is how all real science is done. You hear me, Britain? Do not ask us what our discoveries today will take us in fifty years. We have no idea, really. Other than a gut feeling that stuff like this one day will lead to something we cannot even imagine here and now, and that it is gonna be totally awesome. |
| ** LINK ** |