Synthesis of aziridines
The reaction of N-tosyl imines with in situ generated iodomethyllithium, with a simple and rapid experimental protocol, allows an efficient and general synthesis of aziridines. A reaction of a chiral aldimine derived from phenylalaninal proceeded with high diastereoselectivity. A mechanism to explain this novel reaction is proposed.
J. M. Concellón, H. Rodríguez-Solla, C. Simal, Org. Lett., 2008, 10, 4457-4460.
Aldimines (generated in situ from aldehydes and amines) react readily with ethyl diazoacetate in the presence of 2 mol% of Bi(OTf)3 in [bmim]PF6 to produce the corresponding aryl aziridine carboxylates in high yields with excellent cis-diastereoselectivity.
J. S. Yaday, B. V. S. Reddy, P. N. Reddy, M. Shesha Rao, Synthesis, 2003, 1387-1389.
Montmorillonite K-10 as solid acid catalyzes a stereoselective reaction of imines with ethyl diazoacetate to yield cis-aziridines. The reactions proceeded readily at room temperature in short reaction times, providing the products in very good yields and exclusive selectivity.
D. Borkin, A. Carlson, B. Török, Synlett, 2010, 745-748.
The tertiary amine DABCO catalyzes the reaction of imines with phenacyl bromide derivatives to afford functionalized aziridines in high yields and stereoselectivities in a one-pot process - including the formation of ylides and their precursors.
L. D. S. Yadav, R. Kapoor, Garima, Synlett, 2009, 3123-3126.
A mild, convenient protocol for the synthesis of cis-aziridines employs a catalytic amount of Brřnsted acid. Diazo compound decomposition via alkylation or homocoupling upon exposure to a proton source is slow relative to [2 + 1] annulation in the presence of a Schiff base.
A. L. Williams, J. N. Johnston, J. Am. Chem. Soc., 2004, 126, 1612-1613.
Adducts derived from P(NMe2)3 and α-ketoesters are effectively intercepted by N-sulfonyl imines, affording a range of aziridine-2-carboxylates. The diastereoselectivity of this aziridination depends on steric hindrance from substituents on the substrates.
J. Jiang, H. Liu, C.-D. Lu, Y.-J. Xu, J. Org. Chem., 2017, 82, 811-818.
A clean and fast aziridination of diazoacetamides with N-Boc-imines, as well as N-Cbz-imines, catalyzed by a chiral phosphoric acid in DCM at room temperature achieves excellent yields, diastereoselectivities, chemoselectivities, and enantioselectivities.
X. Zeng, X. Zeng, Z. Xu, M. Lu, G. Zhoung, Org. Lett., 2009, 11, 3036-3039.