Bromocyclization of Alkynyl Guanidine: A New Approach to the Synthesis of Cyclic Guanidines of Saxitoxin

摘要

Bromocyclization of propargyl and homopropargyl guanidines possessing homopropargyl alcohol provides five- and six-membered cyclic guanidines with spiro-hemiaminal, respec-tively, a candidate of precursors for saxitoxin.