Synthesis of the furo[2,3-b]chromene ring system of hyperaspindols A and B

• Danielle L. Paterson and
• David Barker

Beilstein J. Org. Chem. 2015, 11, 265–270, doi:10.3762/bjoc.11.29

• Danielle L. Paterson David Barker School of Chemical Sciences, University of Auckland, 23 Symonds St, Auckland, New Zealand 10.3762/bjoc.11.29 Abstract The synthesis of the unique furo[2,3-b]chromene ring system found in hyperaspidinols A and B, acylphloroglucinols from Hypericum chinense has

• been achieved in twelve steps. By comparison of the NMR spectra of the synthesized compounds with those of the natural products, a relative stereochemistry is suggested, especially that of the ketal carbon. Keywords: acylphloroglucinols; bicyclisation; furo[2,3-b]chromene; fused ketal; Introduction

• both possess a highly functionalised furo[2,3-b]chromene ring system (Figure 2, highlighted in blue) and differ only with the nature of the ketone side-chain. Furo[2,3-b]chromenes have not been reported in any other natural products to date with the closest related system being the chromeno[2,3-b