Synthesis of Substituted Benzofurans by the Tandem One-Pot Intramolecular Carbolithiation-Cyclization-Substitution Sequence

CRISTIAN RODRIGUEZ; NORMA SBARBATI NUDELMAN

SYNTHETIC COMMUNICATIONS

TAYLOR & FRANCIS INC

Lugar: Filadelfia; Año: 2014 vol. 44 p. 772 - 778

0039-7911

A convenient methodology for the synthesis of 3-sustituted-2,3-dihydrobenzofurans was developed based on the tandem intramolecular- carbolithiation-cyclization of 2-bromophenyl-3-phenylprop-2-enyl ether, followed by trapping of the new lithiated intermediate by suitable electrophiles. Several electrophiles were tested, affording good to excellent yields. Alkyl bromides show better results than chlorides and when doubly halogenated alkyl chains are used as electrophiles only one position reacts, affording substituted benzofurans conveniently functionalized to undergo further reactions. The performance of both butyl and phenyllithium as lithiating agents was examined.