Synthesis of Functionalized Bicyclic Triazoles from Chiral Aziridines

Abstract

Enantiomerically pure 3-substituted-5-amino-4-hydroxy-5,6-dihydro-4H-pyrrolo[1,2-c][1,2,3]triazoles were synthesized efficiently from the sequential reactions including a regioselective ring-opening of 1-aziridine-2-yl-propargylic alcohols by azidotrimethylsilane and the subsequent intramolecular 1,3-dipolar cycloaddition between alkyne and azide.

Atom-Economical and Metal-Free Synthesis of Multisubstituted Furans from Intramolecular Aziridine Ring Opening

“…The cyclization with the opening of aziridine for a new heterocyclic compound was observed in our early investigations. 13 However, it has not been shown to make a new ring through the cyclization with the breakage of the aziridine ring in an intramolecular fashion. This extraordinary reaction pathway involving cyclization by heteroatoms at the tether of the starting material with concomitant breakage of the highly strained ring shows a possibility to develop new methods for the preparation of various heterocycles.…”

“…14 Another chemical method to make ring opening easy is to design the starting substrate with olefin for allylic activation. 15 Even though we have studied aziridine for quite a long time, 13 we were not able to open the “unactivated” aziridine rings with the internal oxygen so far because of the intrinsic inertness of the ring opening. Aziridine in this synthesis is “unactivated” with the electron-donating substituent at the ring nitrogen and is quite stable and inert to almost all nucleophiles.…”