First evidence of 1,3-bis-indolylallenes: Generation by a sequential double nucleophilic process from ynones
Résumé
The first examples of 1,3-bis-indol-3-ylallenes (1,3-BIAs) are described. They have been generated by addition of a 3-lithioindole reactant to tetramethylsilane-protected mono- and di-alkynyl ketones. The one-pot preparation of 1,3-BIAs is enabled by both the double electrophilic character of the ynone substrates and the double nucleophilic character of the lithio-enamine function of the indolyl moiety, leading to a transient azafulvenium intermediate. The first examples of 1,3-bis-indol-3-ylallenes (1,3-BIAs) are described. They have been generated by addition of a 3-lithioindole reactant to tetramethylsilane-protected mono- and di-alkynyl ketones. The one-pot preparation of 1,3-BIAs is enabled by both the double electrophilic character of the ynone substrates and the double nucleophilic character of the lithio-enamine function of the indolyl moiety, leading to a transient azafulvenium intermediate.