One-Pot Synthesis of Bis(arylamino)pentiptycenes by TiCl4-DABCO Assisted Reductive Amination of Pentiptycene Quinone

Org Lett. 2024 May 3;26(17):3547-3551. doi: 10.1021/acs.orglett.4c00939. Epub 2024 Apr 24.

Abstract

The previously eight-step synthesis of bis(arylamino)pentiptycenes (2) from pentiptycene quinone (1) can now be achieved in a single step with 18-90% yields through TiCl4-DABCO assisted reductive amination with anilines. Both the dual amination of 1 and the in situ reduction of quinone diimines are unprecedented. The π system of 2 can be further expanded, including the formation of bis(diarylamino)pentiptycenes. This work also provides mechanistic insights into the challenges encountered in the dual reductive amination of 1 with other amines.