Gold(I)-Catalyzed Intramolecular Bicyclization: Divergent Construction of Quinazolinone and Ampakine Analogues

Abstract

A gold(I)-catalyzed cascade intramolecular cyclization of Ugi adducts for the divergent construction of quinazolinone and ampakine analogues has been developed in a rapid, highly efficient and step-economical manner. This protocol shows high yields, excellent functional-group tolerance, broad substrate scope and excellent chemo-and regioselectivity. The practicality of this strategy is further demonstrated by a scale-up reaction. Diverse oligopeptides are also found to be well tolerated, affording polycyclic products decorated with a peptide chain. Letter pubs.acs.org/OrgLett

Post‐Ugi Cyclizations Towards Polycyclic N‐Heterocycles

“…Very recently, we disclosed a gold(I)‐catalyzed intramolecular bicyclization of Ugi‐adducts for the divergent construction of quinazolinones and ampakine analogues with high efficiency and step‐economy (Scheme 15). [24] For Ugi‐adducts derived from terminal alkyne‐tethered aldehydes, exo‐dig cyclization was observed. Interestingly, Ugi‐adducts derived from pent‐4‐ynal or hex‐5‐ynal were well tolerated.…”

Metal‐Free Bicyclization for the Construction of N−O Fused Tetracyclic Isoquinolones

“…Hypervalent‐iodine reagents have been widely used in synthetic chemistry, such as oxidation, [24–26] dearomatization, [27] cyclization, [28–31] alkene difunctionalisation, [32,33] and so on, resulting in numerous important molecules and (poly)heterocycles [34,35] . With our continuing interest in the efficient synthesis of (poly)heterocycles, [36–40] we herein disclose a hypervalent iodine‐mediated bicyclization of N‐alkoxybenzamides for the synthesis of N−O fused tetracyclic isoquinolones (Scheme 1d), which possess good fluorescent properties and antifungal activities towards crop and forest pathogenic fungi.…”

Synthesis of oxindole fused 1,3-oxazepanes via hydride transfer initiated ring expansion of pyrrolidine

“…Van der Eycken et al disclosed an efficient Au( i )-catalyzed intramolecular bicyclization reaction, in which three examples of isoindoline fused 1,3-oxazepane molecules were reported (Scheme 1a). 2 The Mao group described a phosphoric acid catalyzed synthesis of 3,3-disubstituted isoindolinones from tertiary alcohols, and only two examples of oxindole fused 1,3-oxazepane molecules were reported (Scheme 1b). 3 Nevertheless, there are no general methods for the green synthesis of oxindole-fused oxazepane heterocycles.…”