2- Chloroquinoline-cross coupling with

In an application of the Suzuki process, 2-chloroquinoline (141) has been converted into the condensed heterocycle 197 (Scheme 58) (89JHC1589). Thus, metalation, trimethyl borate quench, and hydrolysis affords the stable 3-boronic acid 195 which, upon subjection to cross coupling with ortho-iodo aniline in the presence of Pd(0) catalyst and base, affords the 3-arylquinoline 196. Acid catalysis converts this material into the in-dolo[2,3-f ]quinoline (197) in 35% overall yield. 

The concise formal total synthesis of mappicine was accomplished using an intramolecular hetero Diels-Alder reaction as the key step by M. lhara and co-workers. Introduction of the necessary acetylenic moiety at the C2 position was achieved by the Sonogashira cross-coupling of a 2-chloroquinoline derivative with TMS-acetylene. Several substituents at the C3 position were investigated, and it was found that the unprotected hydroxymethyl substituent gave almost quantitative yield of the desired disubstituted alkyne product. 

Scheme 6.37 A sequential cross-coupling of a 4-(tosylamino)-5-chloroquinoline with tri butylvinyltin to give a diazatricyclic system [145],...

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