Synthesis of trisubstituted furans from 2-bromo-5-methylfuran via halogen migrations and their selective preventions

New trisubstituted furans exhibiting two different substitution patterns were synthesized via lithiation of 2-bromo-5-methylfuran. Choice of appropriate reaction parameters enabled selective halogen dance reactions, affording 2-substituted 3-bromo-5-methylfurans upon quenching with various electrophiles. Moreover, from the same starting material also complete prevention of halogen migration could be achieved, thus providing selective access to 3-substituted 2-bromo-5-methylfurans.