On the move: Decarboxylative coupling of allyl 4‐methyl‐3‐carboxycoumarins provides the products of γ‐allylation of the methyl group rather than the typical regiospecific α‐allylation. Mechanistic studies show that intramolecular proton transfer from the 4‐methyl group to the 3‐carboxylate allows allylation of the remote methyl group. The resulting 4‐butenyl‐3‐carboxyl coumarin undergoes Pd0‐catalyzed decarboxylation to provide the observed products (see scheme).

A new method is developed for the synthesis of spirooxindoles from amines and isatins via C-H functionalization. The reaction leverages the tert-amino effect to form an enolate-iminium intermediate via [1,5]-hydride shift followed by cyclization. Interestingly the hydride migrates to the N atom of a C═N, which is atypical for hydride additions to imines.

Auf Wanderschaft: Die decarboxylierende Kupplung von Allyl‐3‐carboxy‐4‐methylcumarinen liefert die Produkte einer γ‐Allylierung der Methylgruppe – und nicht etwa die der typischen regiospezifischen α‐Allylierung. Mechanistische Studien zeigen, dass ein intramolekularer Protonentransfer von der 4‐Methylgruppe zum 3‐Carboxylat die Allylierung vermittelt und das entstehende 4‐Butenyl‐3‐carboxycumarin dann eine Pd0‐katalysierte Decarboxylierung zu den Produkten eingeht (siehe Schema).

Aspects. -The allylation of coumarins with unusual regioselectivity is investigated and a simple method for γ-allylation of coumarins based on this finding is developed. -(JANA, R.; PARTRIDGE, J. J.; TUNGE*, J. A.; Angew. Chem., Int. Ed. 50 (2011) 22, 5157-5161, http://dx.