The first organo-catalyzed synthesis of imidazolidin-2-ones and imidazol-2-ones via intramolecular hydroamidation of propargylic ureas is reported. The phosphazene base BEMP turned out to be the most active organo-catalyst compared with guanidine and amidine bases. Excellent chemo- and regioselectivities to five-membered cyclic ureas have been achieved under ambient conditions, with a wide substrate scope and exceptionally short reaction times (down to 1 min). A base-mediated isomerization step to an allenamide intermediate is the most feasible reaction pathway to give imidazol-2-ones, as suggested by DFT studies.

Synthesis of Imidazolidin-2-ones and Imidazol-2-ones via Base-Catalyzed Intramolecular Hydroamidation of Propargylic Ureas under Ambient Conditions / Casnati, Alessandra; Perrone, Antonio; Mazzeo, Paolo P.; Bacchi, Alessia; Mancuso, Raffaella; Gabriele, Bartolo; Maggi, Raimondo; Maestri, Giovanni; Motti, Elena; Stirling, András; DELLA CA', Nicola. - In: JOURNAL OF ORGANIC CHEMISTRY. - ISSN 0022-3263. - 84:6(2019), pp. 3477-3490. [10.1021/acs.joc.9b00064]

Synthesis of Imidazolidin-2-ones and Imidazol-2-ones via Base-Catalyzed Intramolecular Hydroamidation of Propargylic Ureas under Ambient Conditions

Casnati, Alessandra;PERRONE, ANTONIO;Mazzeo, Paolo P.;Bacchi, Alessia;Maggi, Raimondo;Maestri, Giovanni;Motti, Elena;Ca, Nicola Della
Supervision
2019-01-01

Abstract

The first organo-catalyzed synthesis of imidazolidin-2-ones and imidazol-2-ones via intramolecular hydroamidation of propargylic ureas is reported. The phosphazene base BEMP turned out to be the most active organo-catalyst compared with guanidine and amidine bases. Excellent chemo- and regioselectivities to five-membered cyclic ureas have been achieved under ambient conditions, with a wide substrate scope and exceptionally short reaction times (down to 1 min). A base-mediated isomerization step to an allenamide intermediate is the most feasible reaction pathway to give imidazol-2-ones, as suggested by DFT studies.
2019
Synthesis of Imidazolidin-2-ones and Imidazol-2-ones via Base-Catalyzed Intramolecular Hydroamidation of Propargylic Ureas under Ambient Conditions / Casnati, Alessandra; Perrone, Antonio; Mazzeo, Paolo P.; Bacchi, Alessia; Mancuso, Raffaella; Gabriele, Bartolo; Maggi, Raimondo; Maestri, Giovanni; Motti, Elena; Stirling, András; DELLA CA', Nicola. - In: JOURNAL OF ORGANIC CHEMISTRY. - ISSN 0022-3263. - 84:6(2019), pp. 3477-3490. [10.1021/acs.joc.9b00064]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11381/2857813
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