First Total Synthesis of the Proposed Structures of Orisuaveolines A and B

First total synthesis of the proposed structures of β ‐indoloquinazoline alkaloids orisuaveolines A and B is reported. The key steps of the synthesis included a Pictet‐Spengler reaction to build a six‐member lactam which further transformed into target molecular by a one‐pot condensation. This synthesis provided an access to the proposed structures of orisuaveolines A and B in a short and convenient manner from inexpensive, commercially available starting materials. The structures of our synthesized products were confirmed by 2D‐NMR experiments.