Oxidations of Cyclic Hemiacetals with Selenium Dioxide

One-Step Synthesis of Laurencione

“…The oxidation of α-methylenecarbonyl compounds with selenium (IV) oxide is a well-known procedure. − We used this method to oxidize the γ-hydroxy ketone 4 to laurencione 1/2 . 5-Hydroxy-2-pentanone 4 , in equilibrium with its cyclic hemiacetal form 3 , is a commercially available product containing about 10% of 5-(4-oxopentoxy)-2-pentanone [(CH 3 COCH 2 CH 2 CH 2 ) 2 O] as an impurity .…”