Palladium(II)-Catalyzed Synthesis of the Formylcarbazole Alkaloids Murrayaline A-C, 7-Methoxymukonal, and 7-Methoxy-<i>O</i>-methylmukonal
作者:Ronny Hesse、Micha P. Krahl、Anne Jäger、Olga Kataeva、Arndt W. Schmidt、Hans-Joachim Knölker
DOI:10.1002/ejoc.201402201
日期:2014.7
We describe the synthesis of the naturally occurring 2,7-dioxygenated formylcarbazolealkaloids7-methoxymukonal, 7-methoxy-O-methylmukonal, and the murrayalinesA–C. The carbazole framework was constructed by a Buchwald–Hartwig amination and a subsequent palladium(II)-catalyzed oxidative cyclization.
The thermolytic deprotection of N-Boc compounds was accomplished using TFE (2,2,2-trifluoroethanol) or HFIP (hexafluoroisopropanol) as solvents. Even though the cleavage of the t-butylcarbamate (Boc) group can be achieved at solvent reflux temperature, the deprotection process was significantly accelerated under microwave-assisted conditions. The practicality of this methodology was demonstrated on alkyl, aryl, and heteroaromatic N-Boc-amines.
General and Facile Synthesis of Indoles with Oxygen-Bearing Substituents at the Benzene Moiety
作者:Yoshinori Kondo、Satoshi Kojima、Takao Sakamoto
DOI:10.1021/jo970377w
日期:1997.9.1
Indoles with oxygen-bearing substituents such as a methoxy or (triisopropylsilyl)oxy group at all of the positions of the benzene moiety were synthesized by cyclization of tert-butyl methoxy(or (triisopropylsilyl)oxy)-2-((trimethylsilyl)ethynyl)phenyl)carba- mates with potassium tert-butoxide in tert-butyl alcohol. The (ethynylphenyl)carbamates were synthesized by the palladium-catalyzed reaction of (trimethylsilyl)acetylene and the corresponding (iodophenyl)carbamates, which were selectively synthesized by directed lithiation of the phenylcarbamates and subsequent iodination.
Studies toward the Synthesis of Potent Anti-inflammatory Peptides Solomonamides A and B: Synthesis of a Macrocyclic Skeleton and Key Fragment 4-Amino-6-(2′-amino-4′-hydroxyphenyl)-3-hydroxy-2-methyl-6-oxohexanoic Acid (AHMOA)
作者:K. Kashinath、N. Vasudevan、D. Srinivasa Reddy
DOI:10.1021/ol303149k
日期:2012.12.21
A first synthetic effort toward total synthesis of highly potent solomonamides is disclosed. An efficient strategy to synthesize this class of compounds, along with the synthesis of a core macrocycle (shown in red) and the key fragment AHMOA, is described.