Reaction of malonates with camphoranile synthesis of 4‐hydroxy‐2‐pyridones attached to the bornane ring system

The reaction of camphoraniles 3a,b with “magic malonates” (bis‐2,4,6‐trichlorophenylmalonates) 4a,b leads to 4‐hydroxy‐2(1H)‐pyridones attached to bornane ring system 6a‐c in good yields. Less satisfactory yields were obtained with the diethyl malonate 5b . The reaction of an excess of diethyl malonate 5 itself with 3b yields the pyrono derivative 7 , which can readily be degraded via the acetyl derivative 8 to the basic structure 9 .