Al‐Catalyzed Facile Construction of Quaternary CC Bonds by the Allylic Substitution of Tertiary Alcohols: A Concise and Formal Synthesis of (±)‐Mersicarpine

Abstract

In close quarters: A concise, high‐yielding, and more sustainable route for the synthesis of (±)‐mersicarpine in nine linear steps from commercially available indole and succinic anhydride is presented (see scheme). It is also demonstrated that the novel protocol can be commonly used for the rapid and flexible construction of a diverse class of mersicarpine analogues.

Enantioselective Total Synthesis and Absolute Configuration Assignment of (+)‐Tronocarpine Enabled by an Asymmetric Michael/Aldol Reaction

“…A chiral catalyst with appropriate ion‐pairing and H‐bonding functionalities as scaffolding elements is expected to form a more rigid transition‐state conformation with the substrates through proper positioning of the interaction sites, and thereby induce better regio‐ and enantioselectivity than a catalyst possessing a single interaction site. Accordingly, a few tartrate‐derived chiral guanidine catalysts were examined using 12 a (Figure ) as a model compound, which could be readily prepared on over a 10 g scale from the known compound 11 through reduction followed by substitution with TMSCN . Disappointedly, the desired reaction did not proceed, with the starting material remaining intact under various conditions, presumably owing to the weak basicity of guanidines.…”

Computergestützte Syntheseplanung: Das Ende vom Anfang

“…Das Programm schlägt vor, die freie Hydroxygruppe zu schützen (blauer Ring um den Knoten), wofür die Methoxymethylgruppe unter den gegebenen Reaktionsbedingungen am besten geeignet ist. Das so erhaltene N ‐Acylindol wird dann mit Oxalylchlorid zum Acylchlorid umgesetzt und anschließend unter Friedel‐Crafts‐Bedingungen zur tricyclischen Zwischenverbindung acyliert. Danach führen die enantioselektive Alkylierung nach der Methode von Enders, (Schritt c) und die reduktive Aminierung (Schritt d) zum 1,2‐ syn ‐Amin.…”

Selective syntheses of leuconolam, leuconoxine, and mersicarpine alkaloids from a common intermediate through regiocontrolled cyclizations by Staudinger reactions

“…2 a The intriguing structural features and biosynthetic connections of these alkaloids make them appealing synthetic targets. 8 To date, eight syntheses of mersicarpine 9 and three syntheses of leuconoxine-type alkaloids have been reported. 9e , g , 10 Leuconolam has been accessed through both total synthesis 9e , g , 11 and oxidative conversion from rhazinilam.…”