New Diene Enables Serial Cycloadditions | Chemical & Engineering News
Volume 93 Issue 21 | p. 33 | Concentrates
Issue Date: May 25, 2015

New Diene Enables Serial Cycloadditions

Organic Synthesis: Chemists create a reagent for tandem reactions to facilitate the synthesis of natural products and imaging agents
Department: Science & Technology
News Channels: Organic SCENE, JACS In C&EN
Keywords: cycloaddition, Diels-Alder, tandem reaction

Chemists have created a new class of diene reagents that enable back-to-back cycloaddition reactions all in one operation. The development could help shorten the synthesis of polycyclic natural products and imaging agents while saving time, cutting cost, and reducing waste (J. Am. Chem. Soc. 2015, DOI: 10.1021/jacs.5b04091). Stanford University’s Paul A. Wender and colleagues came up with the reagent after pondering how nature often achieves chemical complexity through recursive processes—that is, serially repeating a bond-forming event. They decided to try that approach to amplify the synthetic utility of already-useful Diels-Alder and metal-catalyzed cycloaddition reactions. Using the hard-to-prepare and short-lived tetramethyleneethane (TME) diradical as a model, Wender’s team designed 2,3-dimethylene-4-trimethylsilylbutan-1-ol, known as DMTB. This TME equivalent reacts with a variety of dienophiles in an initial cycloaddition, triggering an elimination step that generates a new diene for a second cycloaddition. The Stanford group has used DMTB to carry out a range of consecutive Diels-Alder and metal-catalyzed cycloadditions. In one example, the researchers used it in the synthesis of a new solvatochromic dye, called 6-DMA, which they expect to be a valuable on-off fluorescence probe for studying biological systems.

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Robert Buntrock (May 29, 2015 4:44 PM)
Ah, back to back examples of my favorite reaction; the Diels Alder reaction. Great work.

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