Concise Total Synthesis of Herqulines B and C

A simple
total synthesis of herqulines B and C is reported, modeled
on the reductive biosynthesis reported previously by other researchers.
Commencing from tyrosine, these alkaloids were fashioned through a
dimerization, macrocyclization, and four consecutive reductions. Emerging
from these studies are strategic insights on the synthesis of these
strained alkaloids, as well as mild conditions for the exhaustive
reduction of diketopiperizines.