THE CLAISEN REARRANGEMENT IN SYNTHESIS - ACCELERATION OF THE JOHNSON ORTHOESTER PROTOCOL ENROUTE TO BICYCLIC LACTONES

Catalysis of the Claisen orthoester rearrangement of triethyl orthoacetate and a number of 2-cycloalken-1-ols has been achieved using acidic catalysis and brief microwave thermolysis in DMF. Unlike conventional methods of thermolysis, very high yields of rearranged products are typically obtained in less than ten minutes, and the Claisen products themselves require no further purification. The synthetic utility of the products so obtained is demonstrated in a general synthesis of functionalized bicyclic lactones.