1432-48-0Relevant articles and documents
A Novel Route to Racemic and Nonracemic Products of the Ugi Reaction: Synthesis of Ugi's Labile α-Adducts from Iminoaziridines and Carboxylic Acids, and Their Transformations
Quast, Helmut,Aldenkortt, Sven
, p. 462 - 469 (2007/10/03)
Iminoaziridines (11) are highly reactive synthetic equivalents for three of the four components in the Ugi four-component condensation.Thus, iminoaziridines react rapidly with carboxylic acids at temperatures as low as -20 deg C to afford α-amino isoimides (14), which are identical to the elusive α-adducts of isocyanides in the Ugi reaction. 1,4-Migration of the acyl group (O -> α-N) in 14 furnishes the α-acylamino amides 15.Very little, if any, racemisation is observed when carboxylic acids react with nonracemic iminoaziridines , which are readily available.Mumm rearrangement by O -> N-acyl 1,3-migration to afford α-amino imides (16e,f) competes if the O -> α-N 1,4-shift is slowed down by steric hindrance.The latter acyl shift is catalysed by carboxylic acids while the former is not.The iminoaziridines (R)-11a,c react quantitatively and without racemisation with hydrazoic acid to produce the 5-aminoalkyltetrazoles (R)-21a,c. - Keywords: aziridines; imides; isoimides; rearrangements; Ugi reaction
