A modular strategy involving tertiary amines as templates to build multiple carbon-carbon bonds via reductive cyclization and deaminative contraction steps enables the scalable synthesis of (di)aza5helicenes and (di)aza6helicenes. The methods permit the rapid and gram-scale assembly of key pyridyl-containing dihydroazepines that are advanced using a developed deaminative contraction to access the N-atom positional isomers of pyrido5 and 6helicenes. A telescoped synthesis demonstrates expedited access to (±)-1-aza6helicene, a resolvable helicene valued for its circularly polarized luminescence properties.
Schwartz et al. (Sat,) studied this question.