Advertisement

If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.

ENJOY UNLIMITED ACCES TO C&EN

Synthesis

Copper intermediate sighted

June 25, 2007 | A version of this story appeared in Volume 85, Issue 26

After eluding investigators for more than three decades, the predicted copper(III) intermediate at the heart of many synthetically useful organocopper reactions has finally been stabilized and observed, thanks to a rapid-injection NMR spectroscopic technique (J. Am. Chem. Soc. 2007, 129, 7208). Steven H. Bertz, Michael Murphy, Craig A. Ogle, and coworkers at the University of North Carolina, Charlotte, used an NMR tube chilled to -100 oC as their reaction and observation vessel. They first prepared a solution containing the methylating reagent (CH3)2CuLi•LiCl and trimethylsilyl cyanide. When 2-cyclohexenone was injected into this mixture, it was converted almost exclusively into the copper(III) intermediate shown. This species, the chemists find, persists indefinitely at -100 oC, allowing them to characterize it extensively using NMR techniques. Upon warming to -80 oC, the intermediate breaks down to form the expected product, which has a methyl group attached to the ring carbon that formerly carried the copper. A theoretical study by James P. Snyder and Haipeng Hu at Emory University confirms these results (J. Am. Chem. Soc. 2007, 129, 7210).

Article:

This article has been sent to the following recipient:

0 /1 FREE ARTICLES LEFT THIS MONTH Remaining
Chemistry matters. Join us to get the news you need.