AUyl isocyanide

Kazmaier and coworker described a simple approach to several cyclic peptido-mimetics containing a W-alkylated amino acid via Ugi reaction and a RCM (Scheme 19) [86, 87]. W-terminally protected Aloe amino acids c and aUyl isocyanides d were used in an Ugi-4CR to give the linear precursors e in good yields (72-96%) these were cyclized to the macrocycles f by a subsequent RCM. 

Ddmling and coworkers adapted a four-component Ugi-type reaction sequence to the synthesis of highly substituted 3-pyrrolin-2-ones (Scheme 104 20040L39). The combination of aUyl isocyanide (395), primary amine 396, a-phosphonoacetic acid 397, and a-ketoaldehyde 398 gives the 5-carboxamido-3-pyrrolin-2-one 399. The two-step process involves an Ugi multicomponent reaction followed by an intramolecular Homer/ Wadsworth/Emmons cycHzation. 

A number of isocyanide complexes, [Mo(CN)4(CNR)4] (R = Me, Pr, Bu, aUyl, NCPh2), have been made by the action of RI on Ag4[Mo(CN)g]. The crystal structure of [Mo(CN)4(CNMe)4] shows a dodecahedral geometry, with the CN ligands at 2.177(8) A and the MeNC ligands at 2.148(8) A from the molybdenum.Both C NMR and vibrational spectroscopy indicate that only one isomer is present in solution. 

Zanze and co-workers recently reported an Ugi reaction followed by intramolecular nitrile oxide cycloaddition for the synthesis of novel isoxazo-hnes 130 (Scheme 34) [135]. The substrates required for INOC were synthesized by a multicomponent Ugi reaction utilizing aldehyde 125, aUyl amine 126, isocyanide 128 and -nitro carboxylic acids 127. 

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