Use of a convertible isocyanide for generation of Ugi reaction derivatives on solid support: Synthesis of α-acylaminoesters and pyrroles

Multicomponent Reactions with Isocyanides

“…[ For the synthesis of a-acylamino esters and pyrroles on Rink and Wang resins, cyclohexenyl isocyanide was used and the carboxylic acid linked to the solid phase with succinic anhydride. [119] At the same time, chemists from the company Ontogen reported the synthesis of pyrroles such as 332 by means of U-4CR on NH 2 -functionalized Rink resin 329 and subsequent cycloaddition with alkynes (331) in good yields and with excellent purities after removal from the resin. [120] They applied highly reactive 2-isocyanopyridine as a convertible isocyanide (see also Tetrasubstituted imidazoles like 334 were synthesized by means of U-4CR of a-oxoaldehydes, amines, and carboxylic acids on isocyanide-functionalized Wang resin, affording 333, and subsequent ring closure with ammonium acetate in 16 ± 56 % yield.…”

Solid‐Phase Synthesis of Heterocyclic Systems (Heterocycles Containing One Heteroatom)

“…A slight variant of this reaction was reported by Armstrong wherein resin-bound succinate 61 is used in the Ugi condensation employing 1-isocyanocyclohexene as a convertible isocyanide (Scheme 22.6B) [23]. Münchnone precursors 62 are sufficiently reactive such that heating 62 in toluene containing 10 equiv.…”

Multicomponent Reactions

“…In 1997, the synthesis of small-molecule combinatorial libraries on solid phase by the Ugi reaction was published [56]. Besides pyrroles [57,58] and imidazoles [58], the solid-phase preparations of small ring lactams [59], a-(dialkylamino)-amides, hydantoin-4-imides, 2-thiohydantoin-4-imides, and 5-(1-aminoalkyl)tetrazoles have been described.…”