... Tetrahedron Letters. Volume 52, Issue 13, 30 March 2011, Pages 1509–1511. ... Supplementary data 1. 1 H NMR, 13 C NMR, IR, and HRMS spectra are provided for hibiscone C, for compounds 5, 7, 8, and 13, and for all intermediates between compounds 3 and 5 (Scheme 2). 3b. ...