Indol-2-one intermediates:: Mechanistic evidence and synthetic utility.: Total syntheses of (±)-flustramines A and C

A variety of 3,3-disubstituted 2-indolinones have been prepared by treatment of 3-bromo-3-alkyl-2-indolinones with dienophiles/nucleophiles in the presence of cesium carbonate. Application of this general strategy has facilitated the total syntheses of the reverse prenylated marine natural products (+/-)-flustramine A and (+/-)-flustramine C.