Footnotes

OMe or OAc indicates the specific rotation was measured for that derivative. The values in parentheses are the concentration and the solvent (m = MeOH, e = EtOH, a = acetone, mc = CH₂Cl₂, acn = CH₃CN, no indication = CHCl₃). NR = not reported.

The absolute configuration is known to be as shown.

The absolute configuration is known to be opposite of what is shown.

Not all the stereocenters' configurations have been assigned.

The configuration of a lavandulyl group is assigned in the context of the compound in which it is found.

Isolavandulyl = 2-isopropenyl-5-methyl-5-hexenyl, or −CH₂CH(CMe=CH₂)CH₂CH₂CMe=CH₂. Its configuration is assigned in the context of the compound in which it is found.

ω-Isogeranyl = (2E)-3,7-dimethyl-2,7-octadien-1-yl, or −CH₂CH=CMeCH₂CH₂CH₂CMe=CH₂.

Three different compounds (Fuller 1999, Herath 2005, and Merza 2006) have been named guttiferone I, but one is probably identical to guttiferone G (Ciochina).

This compound was isolated from the same source as its putative enantiomer without the use of chiral columns or a chiral coeluant, so it is highly likely that its structure (or that of its enantiomer) has been misassigned.

The authors' determined the absolute configuration of the side chain experimentally, but they did not determine the configuration of the side chain relative to the core.

The data do not support the assigned configuration.

The authors assign to this compound the structure of hypericumoxide B as proposed in this paper, but they also say that their compound's structure is different from that of hypericumoxide B. The contradiction is resolved by making the configuration of C-32 of this compound consistent with the rule described in this paper.

The text of the paper identifying this compound made it clear that the authors intended the C(7) configuration to be opposite what they showed in the paper's figure.

The authors did not assign the C(7) configuration, but the Grossman–Jacobs rule (see below) suggests the C(7) configuration is as shown.

We have assigned the configuration at stereocenters other than C(7) by comparison to known compounds.

This compound may be identical or enantiomeric to symphonone I or garciyunnanin L.

In their drawing of this compound, Hashida et al. indicated that one of the C(6) substituents was prenyl, but they undoubtedly meant prenylmethyl. In the text, Hashida et al. named the C(18) stereochemistry (α or β) as opposite to what they drew in the figure, but elsewhere in the text they gave evidence that the stereochemistry was indeed as shown in the figure.

The authors' data largely match both this structure and the hemiacetal form of otogirinin B. The authors prefer the latter structure because an NOE interaction expected in the former structure is absent, but they also isolated otogirinin B from this species, and it and its hemiacetal should be in rapid equilibrium, so it seems unlikely that the authors also isolated the hemiacetal. As a result, we propose that the shown structure is the correct one.

The stereocenter configurations named in the text differ from those depicted in the figure.

By comparing this compound's NMR spectra to those of known compounds, we believe the structure is as described in the text.

We suspect that the authors named one or more stereocenters' configurations incorrectly, so we choose to show the structure as depicted in the figure.

One group of authors drew the orientation of the prenyl group that is closest to the bridgehead prenyl group in an ambiguous way, but, as noted in the text, the compound's NOESY data strongly suggest that the prenyl group in question is cis to the adjacent methyl group. It is unclear why the optical rotations of the two isolates are so different.

The argument for the configuration of the side chain is very weak.

The authors draw the structure correctly in Figure 1, where they show the NOE interactions, but they draw the incorrect C5 epimer in Chart 1.

Without citing any evidence one way or the other, the authors assign different configurations to C4 in the figure and the text, but the NOESY spectrum clearly indicates that the configuration shown in the figure is correct.

The authors indicate a particular configuration at the 2H-furan-3-one stereocenter that is not supported by any evidence, so we decline to indicate it here.

The authors assign to this compound the structure of hypericumoxide B as proposed in this paper, but they also say that their compound's structure is different from that of hypericumoxide B. The contradiction is resolved by making the configuration of C-32 of this compound consistent with the rule described in this paper.

The authors propose a structure for hyperpatulol G that is nearly identical to the one previously proposed for hyperhenone H, but the spectra of the two compounds do not match.

The authors propose a structure for hyperfol H that is epimeric to hyphenrone A at C8, with the C7 prenyl and adjacent prenylmethyl groups in a cis orientation, a structure which would be unique among the PPAPs. It is more likely that hyperfol H is epimeric to hyphenrone A at a different position, for example, α to the isobutyryl group.

The authors propose a structure for hyperacmosin I that has the C7 prenyl and C8 prenylmethyl groups in a cis orientation, a feature which would be unique among the PPAPs. However, the ROESY interaction cited as evidence for this orientation is suspect due to peak overlap. It is more likely that these groups are trans to one another, as drawn here.

The authors use X-ray crystallography to determine the absolute configuration, but the calculated Flack parameter has too large an error bar for the assignment to be considered definitive. Instead, the sign of the specific rotation strongly suggests this compound is in the same enantiomeric series as spirohypatone A, not the opposite one as asserted.