NHC-Catalyzed Ring Expansion of Oxacycloalkane-2-carboxaldehydes: A Versatile Synthesis of Lactones
Li Wang, Karen Thai and Michel Gravel*
*Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK S7N 5C9, Canada, Email: michel.gravelusask.ca
L. Wang. K. Thai, M. Gravel, Org. Lett., 2009, 11, 891-893.
DOI: 10.1021/ol8029005 (free Supporting Information)
Imidazolinium-derived carbenes catalyze an efficient ring-expansion lactonization of oxacycloalkane-2-carboxaldehydes to give various functionalized five-, six-, and seven-membered lactones under mild reaction conditions. The electronic nature of the carbene catalyst plays a crucial role for the success of this method.
see article for more examples