Anionic [4+2] cycloaddition of furoindolones (e.g., 7 and 10) has been developed as an effective means to the synthesis of carbazoles. This reaction has been shown to be feasible with a wide variety of Michael acceptors to give carbazoles and fused carbazoles in good yields. The scope and limitations of the reaction have been briefly studied. The nature of N-protection of the furoindolones (cf. 7)
Lateral Lithiation-Initiated Annulations in the Synthesis of 1-Oxygenated Carbazole Alkaloids and a Cycloheptacarbazole
作者:Dipakranjan Mal、Amit Jana、Pallab Pahari
DOI:10.1055/s-0031-1290380
日期:2012.7
Anionic [4+2] annulation of lithiated furoindolones with dimethyl maleate followed by selective demethoxycarbonylation provides an efficient synthetic route to 3-methoxycarbonylcarbazoles. The route has led to the straightforward synthesis of two natural products, namely clausine E, mukonine, and their 4-prenyl analogues. A new route to cyclohepta[d,e,f]carbazole was also uncovered during the investigations