The aza-xylylene Diels–Alder approach for the synthesis of naturally occurring 2-alkyl tetrahydroquinolines

Asymmetric synthesis of 2-alkyl-substituted tetrahydroquinolines by an enantioselective aza-Michael reaction

“…15,16 In this work, electrophilic cyclisations of N-aryl amino acids to 4-keto tetrahydroquinoline were attempted initially under Friedel-Crafts conditions, 17 or by using the Brønsted acid PPA. 18 Application of these procedures to 13, however, led to highly capricious reaction mixtures, from which a small amount of the lactone 14 can be isolated (Scheme 4), i.e.…”

A Formal Total Synthesis of Virantmycin: A Modular Approach towards Tetrahydroquinoline Natural Products

“…With these results in mind, we envisioned a shorter synthesis towards common precursor 3 using our method of carbamate formation [9] which is summarized in Scheme 2. We decided to introduce the iodine atom at a very late stage in our synthetic approach, after cyclization of precursor 8.…”

“…[9] Thus, dry caesium car- Thus, we have completed the synthesis of the advanced precursor 3 in four consecutive steps starting from 9 in an overall yield of 49 %. The remaining steps of the total synthesis towards (±)-virantmycin have already been performed.…”

“…[8] A modified approach developed by our group was applied to the synthesis of several other tetrahydroquinoline natural products. [9] Results and Discussion…”

Asymmetrische Brønsted‐Säure‐katalysierte Substitution von Diarylmethanolen mit Thiolen und Alkoholen zur Synthese von chiralen Thioethern und Ethern

“…Die asymmetrischen Additionen verlaufen unter milden Reaktionsbedingungen in Anwesenheit chiraler Phosphorsäuren und ergeben die entsprechenden Addukte mit exzellenten Ausbeutenu nd Enantioselektivitäten.Früher als Exot wenig beachtet, heute durchaus salonfähig -Aza-ortho-chinonmethide etablieren sich unaufhaltsam zu einer festen Grçße in der organischen Synthesechemie.[1] Es ist vor allem der elegante Zugang zu Te trahydrochinolinen und Indolen [2, 3] sowie die zunehmende Verwendung in komplexen Naturstoffsynthesen (z. B. Virantmycin [4] und Chartellin [5] ), die die Attraktivität dieser vielfältigen Intermediate steigern.…”