INVESTIGATION OF REACTION BETWEEN FULVENES AND α-NAPHTHYLLITHIUM

Abstract

The steric structure and solvent effect of 6,6-dialkylfulvenes in reaction with α-naphthyllithium is studied. It is found for the first time that organolithium causes fulvenes to undergo reductive coupling reaction. In ether-THF, α-naphthyllithium also adds on the exo-cyclic double bond on 6, 6-dimethyl-, diethyl-and 6-methyl-6-ethylfulvene and abstracts α-hydrogen from the side chain of the fulvene in competition with the reduction and reductive coupling reaction. The reductive coupling reaction takes place when α-naphthyllithium reacts with 6-methyl-6-n-propyl-, -n-butyl-, and -i-butylfulvenes. There are various ways of activating 6, 6-polymethylene-fulvenes including tetra-, penta-, and hexamethylenefulvenes, all related with their structures. In ether-petroleum ether (1: 1), except that the 6, 6-tetramethylene-fulvenes undergoes α-hydrogen abstraction reaction, all the other 6, 6-dialkylfulvenes, 6, 6-penta- and hexamethylenefulvenes with α-naphthyllithium mainly undergo addition reaction.From the active fulvenes, some novel substituted or bridged titanocenes and zirconocenes are prepared.