A three-step synthesis of 6-hydroxyharman and 6-hydroxynorharman from benzene and pyridine blocks is described. The preparation of the two α-substituted β-carbolines is based on a new synthetic methodology which involves reactions such as DirectedOrtho Metalation and Heteroring Cross-Coupling.
The paper describes a convenient synthesis of hydroxy-β-carbolines from commercial anisidines based on key steps such as metalation, cross-coupling and cyclization. The first total synthesis of a major cyto-toxic constituent of a marine bryozoan is also reported, the 8-hydroxy-1-vinyl-β-carboline.