Detection of connectivity between equivalent carbons in a C 2 molecule using isotopomeric asymmetry: Identification of hopeaphenol in Carex pumila

In the structure determination of the C 2 symmetrical tetrastilbene hopeaphenol, isolated from Carex pumila , the elucidation of the C‐‐C connectivity between equivalent carbons was needed. From an isotopomeric point of view, three isotopomers, 12 C 12 C, 12 C 13 C and 13 C 13 C, are present with respect to the equivalent carbons connecting each other. Among them, the the 12 C 12 C species is undetectable and the 13 C 13 C species is excluded owing to its low natural abundance. Therefore, only the 12 C 13 C isotopomer is detected in 13 C NMR and this species is not symmetrical. In the H 12 C 13 H system, the separate detection of 1 J (CH) and 2 J (CH) was achieved by the INEPT‐LSPD, COLOC and HMBC methods to demonstrate the connectivity between the equivalent carbons from the viewpoint of isotopomeric asymmetry.