“…Moreover, the preparation of the required cysteine- and aziridine-derived reaction partners is concise and well-established . Various bases, as well as Lewis acids, have been successfully applied for aziridine ring-opening reactions with carbon, nitrogen, sulfur, oxygen, and halogen nucleophiles. , To the best of our knowledge, BF 3 ·OEt 2 is the only Lewis acid that has ever been utilized in the attack of cysteine-derived nucleophile on aziridine. However, as mentioned above, since these reactions typically require large excesses of BF 3 ·OEt 2 , long reaction times, display intolerance toward acid labile protecting groups, and proceed in relatively poor yields, this reaction is unsuitable for large-scale synthesis of β-MeLan derivatives.…”