Science Concentrates SYNTHESIS
New tricks with aryl Grignards Classic organometallic reagent reacts with benchstable oxaziridines to forge C–N and C–O bonds A time-honored laboratory exercise for students of organic chemistry is to make a Grignard reagent from magnesium metal turnings and an organohalide so that they can then use the resulting nucleophile to forge a new C–C bond. Chemists led by Rice University’s László Kürti and Brigham Young University’s Daniel H. Ess now report a way to use stalwart aryl Grignard reagents to fashion C–N and C–O bonds. The chemists found that when they reacted aryl Grignard reagents with a bench-stable, bulky N-H oxaziridine, the nucleophiles attacked the compound’s nitrogen group to generate anilines. Blocking the oxaziridine’s nitrogen with a benzyl group prompted the Grignard to attack the compound’s oxygen atom instead, generating a phenol compound (Nat. Chem. 2016, DOI: 10.1038/nchem.2672). “Our method is really plain and simple,” Kürti says. “You take either of these
PERIODIC TABLE
113
115
Nh
Moscovium
117
118
Ts
O
OH
O
Phenol
C6H5 N O N-Benzyl oxaziridine
O O
MgBr
O N H N–H oxaziridine
Grignard reagent
O
NH2
O
Aniline
Oxaziridines react with an aryl Grignard to generate anilines or phenols reagents, low temperatures, and requires no special equipment, catalysts, or ligands. Kürti and Ess’s team used the transformation with more than 100 different aryl Grignard reagents, including ones that contain various functional groups. “This is a nice new contribution to the current limited repertoire of useful electro-
pharmaceutical motifs, this new reaction is likely to make immediate impact.” Kürti tells C&EN that he hopes a chemical supplier will start selling the oxaziridines so chemists can just buy them instead of synthesizing them. To that end, his lab is making the first 100 g for a well-known reagent company.—BETHANY HALFORD
LAB SAFETY
Nihonium
T Tennessine
oxaziridine reagents and now you have the freedom to take the same aryl Grignard and make the aniline or the phenol out of it.” The reaction, he points out, uses simple
philic oxygen and nitrogen atom reagents capable of delivering these important atoms without unwanted functional groups,” says Jon T. Njardarson, an organic chemistry professor at the University of Arizona, who specializes in developing new reactions. “Given the importance of aniline- and phenol-type structures in
Mc Ogg
Oganesson
The official names for elements 113, 115, 117, and 118 are nihonium, moscovium, tennessine, and oganesson, the Internationial Union of Pure & Applied Chemistry (IUPAC) announced on Nov. 30. Although the abbreviation for tennessine, Ts, is also used for the tosyl group, IUPAC notes that other chemistry abbreviations have multiple meanings—such as Ac for actinium and acetyl—and that the meaning should be clear given the context in which the abbreviation is used.
ACS journals enact acrossthe-board safety policy American Chemical Society journals will have a new safety reporting requirement starting in 2017: Authors must “address and emphasize any unexpected, new, and/or significant hazards or risks associated with the reported work,” says an ACS Central Science editorial describing the change (2016, DOI: 10.1021/acscentsci.6b00341). ACS Publications editors and staff took a closer look at how the journals addressed safety after a “confluence of events” that included high-profile accidents and a survey of safety policies of chemical journals (J. Chem. Health Saf. 2016, DOI: 10.1016/j.jchas.2015.10.001), says Sarah Tegen, vice president for global editorial and author services at ACS. ACS also publishes C&EN. Previously, individual journals set their own safety policies. The journals’ Peer Review Advisory
Group (PRAG) developed the new wording to make it clear that good safety practice is vital while also being broad enough to be applicable across all the fields that the journals represent, Tegen says. Reaction from journal editors has been positive. “There is a strong sense that this is the right thing to do,” says Inorganic Chemistry editor-in-chief and PRAG member William B. Tolman. Beyond including the language in guidelines for authors and reviewers, ACS is leaving individual journal editors to decide how the new requirement is implemented. Tolman, for example, has already added a required check box in a form filled out by Inorganic Chemistry reviewers that asks whether authors have appropriately addressed safety. “It’s a simple and easy way to get the journal community to start paying attention to it,” he says.—JYLLIAN KEMSLEY
DECEMBER 5, 2016 | CEN.ACS.ORG | C&EN
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