 Secondly, the yield for electron rich and electron poor arenes was improved via minor modifications to the reaction procedure (higher catalyst loading, higher temperature, longer reaction time), although no ortho-substituted aryl groups were included in this publication.In 1995, back to back studies from each lab showed that the couplings could be conducted with free amines in the presence of a bulky base (NaOtBu in the Buchwald publication, LiHMDS in the Hartwig publication), allowing for organotin-free coupling.Though these improved conditions proceeded at a faster rate, the substrate scope was limited almost entirely to secondary amines due to competitive hydrodehalogenation of the bromoarenes.