Stereoselective Formation of Three Carbon-Carbon Bonds by Cascade Reaction with Enolate Anion: Synthesis of Tricyclo[6.2.2.01,6]dodecane and Tricyclo[5.3.1.03,8]undecane Derivatives
作者:Masataka Ihara、Kei Makita、Yuji Tokunaga、Keiichiro Fukumoto
DOI:10.1021/jo00099a034
日期:1994.10
Reaction of 6-[5(E)-6-(methoxycarbonyl)hex-5-enyl]-2-cyclohexen-1-one (1) with LHMDS, followed by one-pot treatment with CH2O, resulted in a cascade Michael-Michael-aldol reaction, producing hydroxymethylated tricyclo[6.2.2.0(1,6)]dodecane 3. The methylated tricyclo[5.3.1.0(3,8)]undecane 21 was obtained by a Michael-Michael-substitution reaction, performed by reaction of 5-[4(E)-5(methoxycarbonyl)pent-4-enyl]-2-methyl-2-cyclohexen-1-one (11) with LHMDS and one-pot treatment with MeI in the presence of HMPA. Michael-Michael-aldol reactions of 11 were also carried out with LHMDS followed by several aldehydes to provide tricyclo[5.3.1.0(3,8)]undecane derivatives 22, 23, and 24, respectively. The importance of intramolecular coordination wit h lithium for the double Michael reaction was supported by an experiment utilizing the corresponding (Z)-isomer 13.