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DOI: 10.1055/s-0033-1340447
Catalytic Alkenylation of Neopentyl Palladium Species Using N-Tosyl Hydrazones
Publication History
Publication Date:
13 December 2013 (online)
![](https://www.thieme-connect.de/media/synfacts/201401/i_l157_s1_10-1055_s-0033-1340447.gif)
Significance
Palladium-catalyzed Heck-type cascades have long been used to install molecular complexity in a single transformation. In early pioneering work, Negishi and Grigg have reported cascade processes involving carbonylation sequences, Stille and Suzuki couplings, as well as C−H functionalization as terminating steps. However, despite these advances, terminations involving palladium carbenes have been far less explored. Gu and co-workers report the combination of N-tosyl hydrazone derived carbenes and in situ generated alkyl palladiums in a new alkenylation reaction.
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Comment
The authors present a palladium-catalyzed Heck-type cascade reaction en route to alkene products. By terminating the cyclization sequence with a reaction with N-tosyl hydrazones, products can be obtained with high E/Z ratios. The method benefits from the ability to generate diverse hetero- and carbocycles in good to excellent yields under relatively mild conditions, using a simple palladium(II) pre-catalyst. Cyclization onto electron-deficient alkenes was shown to be preferred in a competition experiment involving a diene substrate.
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![](https://www.thieme-connect.de/media/synfacts/201401/i_l157_s1_10-1055_s-0033-1340447.gif)