Aryne Multicomponent Reactions by Directed C−H Activation

Arylation via ortho C−H activation by the aid of directing groups has been explored recently by many researchers. Herein, a palladium-catalyzed C−H arylation using 8-aminoquinoline as a bidentate directing group has been developed. The reaction furnishes only C−H arylation, unlike previous methods where cyclization to corresponding isoquinolones is observed. More interestingly, sequential C−H functionalization was observed when methylacrylate and acrylonitrile was added; this led to C−H olefination with the aryl group, which was installed from the aryne precursor.     

Papieruntersuchung

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Analyse des Eisens

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A concise synthesis of ent-Cholesterol

ent-Cholesterol was synthesized in 16 steps from commercially available (S)-citronellol. The overall yield for the synthesis was 2.0%. This route is amenable to gram-scale preparation of ent-cholesterol. Isotopic incorporation near the end of the synthesis was achieved using labeled methyl iodide. This synthesis is the most practical to date and will make ent-cholesterol more readily available to use as a probe of the function and metabolism of cholesterol.