ChemInform Abstract: ASYMMETRIC SYNTHESIS VIA HETEROCYCLIC INTERMEDIATES, XXIV. ENANTIOSELECTIVE SYNTHESIS OF (R)‐α‐METHYLTRYPTOPHAN METHYL ESTER AND D‐TRYPTOPHAN METHYL ESTER BY THE BISLACTIM ETHER ROUTE

Abstract

Durch Umsetzung der lithiierten Bislactimether (Ia)‐(Ic) mit dem Bromid (III) werden stereoselektiv die Alkylierungsprodukte (IVa)‐(IVc) erhalten, die nach Spaltung des Pyrazinsystems und Abspaltung der Schutzgruppe die im Titel genannten Aminosäuren (VIa) und (VIb) ergeben.

Utilization of an Intramolecular Hydrogen Bond To Increase the CNS Penetration of an NK1 Receptor Antagonist

“…There is literature precedent for the enantioselective synthesis of α-methyltryptophan, and these methods include chemical syntheses with varying degrees of enantiopurity − and enzymatic resolutions which give excellent enantioselectivity. , As a consequence of our previous success with the method described by Crich et al . in which the α-alkylation of Trp was achieved with high enantioselectivity, it was decided to pursue this approach in attempting to introduce α-substituents incorporating heteroatoms stereoselectively.…”

Chemistry of the Hexahydropyrrolo[2,3-b]indoles: Configuration, Conformation, Reactivity, and Applications in Synthesis

“…Overall, the process of formation of 5 or 6 followed by alkylation and ring cleavage constitutes a novel example of Seebach's principle of self-regeneration of chirality 37 and enables the formation of a range of R-alkyl Ltryptophan derivatives from L-tryptophan itself with complete retention of configuration. 38,39 Oxidative cleavage of the indole ring in 41 with catalytic ruthenium trichloride and sodium metaperiodate gave the R-methyl-L-aspartate 47 (Scheme 2). Alternatively, oxidative cleavage of 44 gave the enantiomerically pure R-disubstituted amino acid derivative 48, whose chirality derives solely from the differential protection of the two side chains.…”