Rhodium-catalyzed isomerization of 4-pentenals into 3-pentenals by endocyclic b-H elimination.

Scope of the chemo- and stereoselective isomerization of 4-pentenals into (E)-3-pentenals. All of the yields are given for isolated products as the average of two experiments; see the Supporting Information. [a] Yield determined by 1H NMR spectroscopy in [D6]acetone in the presence of an internal standard. [b] Room temperature.