Chiral synthesis quinolines

In the same context, the synthesis of chiral l-(2-methylthio-l-naphthyl)iso-quinoline depicted in Scheme 1.35 was reported by the same authors on the... 

Other indoles that have been prepared using the Sonogashira coupling and cyclization sequence include 5,7-difluoroindole and 5,6,7-trifluoroindole [219], 4-, 5-, and 7-methoxyindoles and 5-, 6-, and 7-(triisopropylsilyl)oxyindoles [220], the 5,6-dichloroindole SB 242784, a compound in development for the treatment of osteoporosis [221], 5-azaindoles [222], 7-azaindoles [160], 2,2-biindolyls [223,176], 2-octylindole for use in a synthesis of carazostatin [224], chiral indole precursors for syntheses of carbazoquinocins A and D [225], a series of 5,7-disubstituted indoles [226], a pyrrolo[2,3-eJindole [226], an indolo[7,6-g]indole [227], pyrrolo[3,2,l-y]quinolines from 4-arylamino-8-iodoquinolines [228], optically active indol-2-ylarylcarbinols [229], 2-alkynylindoles [176], 7-substituted indoles via the lithiation of the intermediate 2-alkynylaniline derivative [230], and a variety of 2,5,6-trisubstituted indoles [231], This latter study employs tetrabutylammonium fluoride, instead of Cul or alkoxide, to effect the final cyclization of 215 to indoles 216 as summarized here. 

Skraup quinoline synthesis, 443 Smiles rearrangement, phenothiazine, 534 Spiroalkylation, 222, 280 Spirocyclization, conjugate addition, 386 Spiroimidazolone formation, 335 Spiropyrazolopiperidine, 375 Stannylation, alkyne, 15 Stereoselective dehydration, 198 Grignard addition, 198, 199 reduction, 129, 226 hydroxyketone, 400 iminoketone beta, 553 oxazaborohydride, 585 transfer chirality, 321 Stilbene formation, self alkylation, 525 Stobbe condensation, benzophenone, 103... 

Since then, similar reactions have been reported by different authors examples include the synthesis of quinolines [180] or even pyrroles [181] or enamines from chiral amines [182]. Indoles can also participate in these reactions [183]. 

Kametani et al. (66) also succeeded in the asymmetric synthesis of xylopinine by applying 1,3-asymmetric induction to enamide photocyclization. Acylation of L-3,4-dimethoxyphenylalanine, followed by the Bischler-Na-pieralski cyclization of the resulting amide, gave the chiral 3,4-dihyroiso-quinoline 159, which was then acylated to afford the chiral enamide 19. 

M. Yamato, K. Hashigaki, S. Ishikawa, N. Qais, Syntheses of chiral oxazolo[2,3-a]tetrahydroiso-quinoline and its asymmetric alkylation. Synthesis of (S)-(-)- and (R)-(-l-)-salsolidines, Tetrahedron Lett. 29 (1988) 6949. 

The closely related camptothecin 133 is more complicated because it is chiral. Close analogues (topotecan and irinotecan) are in use as anti-cancer drugs. As these compounds differ only by substitution on the quinoline, synthesis of the enantiomerically pure pyridone 135 is obviously of prime importance. 

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