S. Achab et al., AN EXPEDITIOUS SYNTHESIS OF STRUCTURAL ANALOGS OF THE MARINE CYTOTOXIC AGENTS GROSSULARINES-1 AND GROSSULARINES-2, Tetrahedron letters, 36(15), 1995, pp. 2615-2618
A short access to 2-carbethoxy-3-(5-imidazolyl)indoles (13, 14, 16), f
eaturing Pd-catalyzed cross coupling between 3-iodoindoles (10-12) and
imidazolostannane (9) has been developed. These derivatives when subj
ected to tandem modified Curtius rearrangement-intramolecular electroc
yclization led to the pyridones (19-23) which are key intermediates in
the synthesis of the analogs (31), (33) and (36) of the naturally occ
urring cytotoxic alpha-carbolines grossularines-1 and -2 (1,2).