Ring-expansion protocol: preparation of synthetically versatile dihydrotropones.
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.
Do
Young-Sun
YS
Department of Nano Science and Engineering, Myong Ji University, Yongin, Kyunggi-Do 449-728, Korea.
Sun
Ruiying
R
Kim
Hee Jin
HJ
Yeo
Jung Eun
JE
Bae
Sung-Hee
SH
Koo
Sangho
S
D006018:Glycols / Q000737:chemistry; D010084:Oxidation-Reduction; D013237:Stereoisomerism; D014334:Tropolone / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry
D006018:Glycols; D014334:Tropolone; C003730:tropone