Ring-Opening Reactions of the N-4-Nosyl Hough–Richardson Aziridine with Nitrogen Nucleophiles

Abstract

Dinosylated α-d-glucopyranoside was directly transformed into α-d-altropyranosides via in situ formed N-4-nosyl Hough-Richardson aziridine with nitrogen nucleophiles under mild conditions in fair to excellent yields. The scope of the aziridine ring-opening reaction was substantially broadened contrary to the conventional methods introducing solely the azide anion at high temperatures. If necessary, the N-4-nosyl Hough-Richardson aziridine can be isolated by filtration in a very good yield and high purity.

Synthesis of Enantiomerically Pure 5-Substituted Piperazine-2-Acetic Acid Esters as Intermediates for Library Production

“…Closer examination of the ammonia displacement reaction by LC–MS revealed the formation of the N -nosyl aziridine 14 as a major constituent of the product mixture. The aziridine presumably arises from deprotonation of the N -nosyl group by ammonia followed by intramolecular mesylate displacement. − Alkyl-substituted N -nosyl aziridines are known to react with nucleophiles to give regioselective ring-opened products. , Therefore, we rationalized that aziridine generation followed by introduction of the second nitrogen in a protected form would directly lead to orthogonally protected diamines analogous to 10 . Fortunately, a prior example of such a transformation had been reported, encouraging us to investigate this strategy (Scheme ).…”