Factors influencing prenylation of an aromatic organolithium

Abstract

An apparently routine metal–halogen exchange (MHE) reaction gave variable low yields under typical conditions. 13C and 7Li NMR studies suggested a diversity of organolithiums were formed in the MHE reaction leading to a plethora of products on subsequent electrophilic aromatic substitution with geranyl bromide. A reversal of reagent addition simplified the 7Li NMR spectrum and the product distribution, in addition to increasing the isolated yield of the desired product from a variable 5-40% to a consistent 65%.