Do Young-Sun, Sun Ruiying, Kim Hee Jin, Yeo Jung Eun, Bae Sung-Hee, Koo Sangho
Department of Nano Science and Engineering, Myong Ji University, Yongin, Kyunggi-Do 449-728, Korea.
J Org Chem. 2009 Jan 16;74(2):917-20. doi: 10.1021/jo802064c.
A ring-expansion protocol that consisted of the 1,2-addition of various enolate nucleophiles to 6-trimethylsiloxy-2-cyclohexene-1-one (1) and the NaIO(4)-promoted oxidative ring opening of the resulting diols 2, followed by an intramolecular Knoevenagel condensation, furnished versatile dihydrotropones 6. Maintaining Z-configuration in the oxidative ring-opening products 3 is crucial for the success of the ring-expansion strategy. Dihydrotropones 6 are ripe for further elaborations such as oxidation to tropones 8 and Diels-Alder reaction with the Danishefsky's diene 10 to afford polycyclic compounds 12.
