Gold-catalyzed formation of pyrrolo- and indolo-oxazin-1-one derivatives: The key structure of some marine natural products

• Sultan Taskaya,
• Nurettin Menges and
• Metin Balci

Beilstein J. Org. Chem. 2015, 11, 897–905, doi:10.3762/bjoc.11.101

• into 3,4-dihydropyrrolo- and indolo-oxazin-1-one derivatives by a gold(III)-catalyzed cyclization reaction. Some of the products underwent TFA-catalyzed double bond isomerization and some did not. Cyclization reactions in the presence of alcohol catalyzed by Au(I) resulted in the formation of

• hemiacetals after cascade reactions. Keywords: alkyne cyclization; gold-catalyzed reaction; indolo-oxazin-1-one; marine natural products; pyrrolo-oxazin-1-one; Introduction Pyrrole-containing heterocycles are widely distributed within a large number of natural products and biologically active molecules [1

• of pyrrolo- and indolo-oxazin-1-one derivatives. The key step was a gold-catalyzed cyclization reaction of N-propargyl-substituted pyrrole and indole carboxylic acid derivatives. The hydroxy groups of carboxylic acids attacked the activated triple bond to form 6-exo-dig cyclization products, oxazin-1