H Mayr et al, (JACS, 2013, 135 (17), 6579) reports on the electrophilicities of benzaldehyde-derived iminium ions, producing a scale as shown below which I thought may be of use to chemists in the battle toward achieving the balance between a nucleophile and electrophile. Good luck!
A slightly older article – which I must have missed on first pass! M Kunishima et al (Org Lett, 2012, 14 (19), 5026) describe the synthesis and use of a novel acid-catalysed O-benzylating reagent.
Regular readers of my chosen articles will know that I like multicomponent reactions, so it will come as no surprise to note my interest in the paper by P Kim et al (Angew Chem Int Ed, 2013, 52 (29), 7564).
Some time ago I had to scale a palladium-catalysed aminocarbonylation reaction from 10’s of grammes to about 10kg input – the process in this case worked very nicely and we were able to operate at atmospheric pressure as opposed to the 3-5bar used in lab scale by our client.
I was attracted to the paper by H Guan et al (Angew Chem Int Ed, 2013, 52 (29), 7523) since it describes what appears to be a nice and convenient means to add the cyanomethyl group to an aldehyde.
I have periodically mentioned frustrated Lewis pairs (FLPs) in my newlsetter items since I find this a fascinating area of chemical research which may well have great potential to open a new non-metal field of catalysis.
A few years ago chemists at Boehringer Ingelheim reported the reductive acetylation of oximes1 to produce N-acetylenamides which are good substrates for asymmetric hydrogenation.
The reaction can be extended to produce chiral pyrrolidones if chiral iridium catalysts are first used to make the allylic formamide, followed by Ru catalysed cyclisation ( J Amer Chem Soc, 2013, 135, 6814).
Since the Mitsunobu reaction was first introduced in 1967, it has proved an invaluable reaction in discovery chemistry yet process chemists have been reluctant to use it on large scale because of the toxicity of DEAD, thermal hazards and the difficulties with waste streams.
R A Shenvi and D J Jansen (JACS, 2013, 135 (4), 1209) published a nice paper outlining the synthesis of a complex target molecule without the use of protecting groups. Besides being a nice piece of work, I thought it’d provide a nice lunch-time brain-teaser for those of you interested in spotting the odd named reaction and working out mechanisms in the route.
During my reading of the literature I like to look for what I consider more unusual topics or information that could be useful in a different context and for this reason I am often attracted to reports about solvents, looking for the potential for this class of material to act not simply as a carrier or facilitator for our chemistry, but also to participate.
Jacobsen and colleagues (JACS, 2013, 135 (18), 6747) presented a very nice communication describing the organocatalysed generation of N-hydroxypyrrolidines with modest to high enantioselectivity.
I was intrigued to see a paper describing the formation of enantiomerically pure α-functionalised Grignard reagents (P O’Brien et al, JACS, 2013, 135 (21), 8071). Perhaps I had missed earlier reports, but was especially interested in the generation of the configurationally stable ‘anionic’ centre.
Michael B. Smith, Wiley, 2013, 2047 + xxv pages, £83.50, ISBN 987-0-470-46259-1
Good news! The 7th edition of “March’s” is now available.
The bad news! It’s even heavier than the 6th edition. Of course this means that the new edition has been rewritten and updated to include advances in organic chemistry in the period 2005-2010, with more than 5500 new references added.
Neil Winterton, RSC Publishing, 2011, 480 + xiii pages, £62.99, ISBN 987-1-84755-813-8
The scope of the book is to explain the concept of sustainability, to highlight the role of science and technology in moving towards sustainable development, and to use examples of new approaches to chemistry to meet these needs. Metrics is given a central role in the discussions.