We present herein a highly atroposelective
indolization
for the
efficient synthesis of 1,1′-biheteroaryls bearing a chiral
N–N axis. Under the cooperative catalysis of chiral phosphoric
acid and InBr3, the reactions between 2,3-diketoesters
and 1,3-dione-derived enamines resulted in a highly enantioselective
construction of 1,1′-pyrrole-indoles with up to 92% yield,
94% enantiomeric excess (ee), or bisindoles in up to 92% ee. Derivatizations
of these compounds to diverse functionalized N–N linked axially
chiral biheteroaryls have also been demonstrated.