REACTION OF TRI-2-THIENYLMETHYLLITHIUM WITH ALKYL-HALIDES - SUBSTITUTION ON CARBANION CENTER VS THIOPHENE RING

Tri-2-thienylmethyllithium, produced by treatment of tri-2-thienyl-methane with butyllithium in the presence of N,N,N',N'-tetramethyl-ethylenediamine at -78-degrees-C in tetrahydrofuran, reacts with primary alkyl halides to give the alkylated products on the carbanion center nearly quantitatively, while the reaction with secondary and tertiary alkyl halides affords not only the substitution products at the carbanion center but also those at the 3-position of the thiophene ring.