The formation of 2-hydroxy-4-hydroxymethyl-3-(indol-3-yl)cyclopent-2-enone derivatives from ascorbigens

A facile preparation is described of 3-(indol-3-yl)-2-hydroxy-4-hydroxymethylcyclopent-2-enone and its N-derivatives in 15–40% yields by the degradation of ascorbigen or its N-derivatives in a warm solution of l-ascorbic acid through a sequential domino reaction. The same cyclopentenone derivatives were obtained in 30–40% yields by the condensation of ( N-alkylindol-3-yl)glycolic acids with ascorbic acid. 2,6-Dihydroxy-1-(indol-3-yl)hexa-1,4-diene-3-one and 2-hydroxy-4-hydroxymethyl-5-(indol-3-yl)cyclopent-2-enone were identified as intermediates in this reaction.