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Novel transfer hydrocyanation

21 February 2016 - Orgo

transfer hydrocyanation.PNGNews in organic hydrocyanation. Reliance on hydrogen cyanide for any alkene hydrocyanation is taken for granted. Major disadvantages though: the gas is a poison for humans, the gas also tends to poison the catalyst. In a recent Science article Fang, Yu & Morandi describe an alternative approach based on transfer hydrocyanation (DOI). As in transfer hydrogenation this process does not involve the actual gas (HCN in this case) but rather a convenient and safe carrier molecule. In a typical recipe the carrier molecule is isovaleronitrile, the catalyst is bis(cyclooctadiene)nickel(0), the ligand is DPEphos, the Lewis acid is aluminium chloride and the reaction conditions toluene @100°C / multihours. The driving force is expulsion of isobutylene. Successful substrates: styrene, (E)-Stilbene, norbornene and cyclohexene. With norbornadiene as an acceptor a retro-hydrocyanation reaction is also possible. The driving force now is strain-relase. The acknowledgements mention a patent application, could be worth something.

Sci Hub pirates

10 February 2016 - Christmas arriving early

scihub.PNGWith thanks to Rich Apodaca for the Twitter alert. A pirate-bay for science enthusiasts has been around for some time called Sci-Hub and without me knowing about it. Has Christmas arrived early this year? Or should this blog behave responsibly and condemn it? It is not like I lack access to the chemical literature. A very nice local university has been providing me with a free library card for many years now allowing me to download articles. The only catch is that I have to drive up there and work from a local desktop if not alrady occupied by one of those pesky students. Actual online access would be super. Rich is happy with the level of access he gained from the website. This blog did it's own field-test. Positives scores on an Organic Letters article (2015) DOI. A 2015 Angewandte article (DOI) can be accessed, Stu will be alarmed to learn that his Nature Chemistry is up for grabs as well, including those articles from the current issue (DOI). Same goes for Elseviers Tetrahedron. In each case the pdf file is embedded but can easily be retrieved from the html content. If you want to do your own field test then hurry: as the Wikipedia article explains an army of Elsevier lawyers is working around the clock to have the site shut down. Do read theatlantic.com article on the topic