Scalable, Electrochemical Oxidation of Unactivated C–H Bonds
2017 · paper · Chemistry
Presents an electrochemical oxidation of unactivated C–H bonds using quinuclidine as a redox mediator with carbon and nickel electrodes. It selectively oxidizes methylene and methine groups with good functional group compatibility, demonstrated on a 50 g scale with sclareolide.
Checked: PDF from europepmc.org, fetched 4 Oct 2026. Page numbers are those of that PDF.
3 findings
Reference or label Text: "nickel, copper, and even stainless steel were all found to be viable materials for the cathode (entries 13−15)"; in Figure 1B entries 13-15 are "stainless steel cathode", "Cu cathode" and "Al cathode". Nickel is the standard condition, not one of these entries, and aluminium (entry 15, 36%, 2.1/1) is not mentioned.
- p. 1 Body text, right column, last lines (continues on PDF page 2)
while nickel, copper, and even stainless steel were all found to be viable materials for the
- p. 2 Body text, left column, first line
cathode (entries 13−15)
- p. 2 Figure 1B table, entry 15
Al cathode
- p. 1 Results text, last paragraph of page (continues on page 2)
while nickel, copper, and
Only the authors can say what is right here.
Judge's note: Read the table on an enlarged render of page 2: entry 13 stainless steel 49% (2.8/1), entry 14 Cu 45% (6/1), entry 15 Al 36% (2.1/1); the header scheme gives 'RVC anode / Ni cathode' as the standard. The sentence spans pages 1-2. The cited range includes an aluminium entry the sentence does not describe and no nickel entry; either the range should be 13−14 (with nickel as the baseline) or aluminium was meant to be listed. Nothing elsewhere in the article explains it.
Second check: another model agreed
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Reference or label Figure 1C legend lists seven entries including "TEMPO (G)" and "HOBt (H) + 2,6-lutidine", but these two have no line sample and only five traces are visible in the plot.
- p. 1 Figure 1C, legend
TEMPO (G)
- p. 2 Figure 1C, legend
HOBt (H) + 2,6-lutidine
Only the authors can say what is right here.
Judge's note: Enlarged render of Figure 1C (PDF page 2; the cluster's first location says page 1 but the figure is on page 2). Legend keys are present for Quinuclidine (A) + HFIP (green), Aceclidine (B) + HFIP (yellow dashed), DABCO (C) + HFIP (grey), TCNHPI (E) + 2,6-lutidine (red double line) and NHPI (F) + 2,6-lutidine (blue dashed). The TEMPO (G) and HOBt (H) + 2,6-lutidine entries have no key, and I count five curves in the plot. The traces may have been lost in production or drawn in a colour that does not show; only the authors can say.
Second check: another model agreed
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Reference or label Figure 1C legend reads "TCNHPI (E) + 2,6-lutidine" and "NHPI (F) + 2,6-lutidine", whereas Figure 1B defines "X = H: NHPI (E)" and "X = Cl: TCNHPI (F)" and the text uses "TCNHPI (F)" and "NHPI (E)".
- p. 2 Figure 1C, legend
TCNHPI (E) + 2,6-lutidine
- p. 2 Figure 1C, legend
NHPI (F) + 2,6-lutidine
- p. 2 Figure 1B, Mediators panel
X = H: NHPI (E)
- p. 1 Body text, right column
The mixtures of TCNHPI (F) or NHPI (E) with 2,6-lutidine
Judge's note: Read both panels on enlarged renders of page 2 and the text on page 1 ('TCNHPI (F), a highly effective mediator', 'The mixtures of TCNHPI (F) or NHPI (E) with 2,6-lutidine'). The letters in the Figure 1C legend are the reverse of the definition in Figure 1B and of every use in the text. No alternative lettering is defined anywhere. Most likely the letters in the legend are swapped (E and F should be exchanged); if instead the names are swapped, the two traces are misattributed, which the authors would need to confirm.
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7 minor (typos and the like; most checked by the judge only)
Wording Text says "tertiary amines (e.g., A, B, and C) were singularly successful (entries 1−5)" and "NMO (D), TEMPO (G), and HOBT (H) have all proven ineffectual", but Figure 1B gives 9% for C (entry 2) and 19% for D (entry 3), and entries 3-5 are D, "E, F, G, or H as the mediator/no mediator" and "0.4 equiv. of A".
- p. 1 Body text, right column, first lines
tertiary amines (e.g., A, B, and C) were singularly successful (entries 1−5).
- p. 2 Figure 1B table, entries 1-5
D as the mediator
- p. 2 Figure 1B table, entry 4
E, F, G, or H as the mediator/no mediator
- p. 1 Results text, optimisation paragraph
tertiary amines (e.g., A, B, and C) were singularly successful
Judge's note: Read Figure 1B on an enlarged render of PDF page 2: entry 1 B 39% (2.1/1); entry 2 C 9% (2.0/1); entry 3 D 19% (1.1/1); entry 4 E, F, G or H/no mediator <5%; entry 5 0.4 equiv of A 30%. The N-oxide D gave about twice the yield of the tertiary amine C, yet the text calls C merely 'inferior' and D 'ineffectual'; D does have the worst selectivity (1.1/1), which may be what the authors mean. The range 'entries 1−5' covers the whole mediator screen plus a loading experiment, not only tertiary amines; the same paragraph cites entries 4 and 5 separately. Both points are loose wording rather than a wrong number. No explanatory statement elsewhere in the article.
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Wording Text: "The yields and selectivities were comparable to those of TFDO oxidation"; Scheme 1 gives for 7 "56% (δ:γ = 1.9:1)" against "[TFDO]: 95% (δ:γ > 20:1)", for 3 "72% (δ:γ = 3:1)" against "[TFDO]: 80% (δ:γ = 7:1)", and for 6 2.3:1 against 5.6:1.
- p. 2 Left column, scope paragraph
and selectivities were comparable to those of TFDO
- p. 3 Scheme 1, compound 7
7, 56% (δ:γ = 1.9:1)
- p. 3 Scheme 1, compound 7
95% (δ:γ > 20:1)
- p. 3 Scheme 1, compound 3
80% (δ:γ = 7:1)
Judge's note: Read Scheme 1 on an enlarged render of page 3. Where a TFDO comparison is shown: 3 72% (3:1) vs 80% (7:1); 4 56% (3.2:1) vs 60% (1.9:1); 6 78% (2.3:1) vs 92% (5.6:1); 7 56% (1.9:1) vs 95% (>20:1); 9 80% vs <5%; 10 63% (2.4:1) vs 42% (1:1.1); 2 51% (C2:C3 4.6:1) vs 47% (1:3.5). The methods differ markedly in both directions for several substrates, and the following paragraphs of the paper discuss some of those differences themselves. 'Comparable' is a loose general summary; this is a wording point only.
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Wording Note 14: "Yields and selectivity of compounds 4, 8, 9, 10, and 2 through TFDO oxidation were determined experimentally. See SI for detailed information." Scheme 1 shows a [TFDO] line for 4, 9, 10 and 2 but none for 8 ("8, 52% (γ:δ = 2.4:1)").
- p. 4 Reference 14
Yields and selectivity of compounds 4, 8, 9, 10, and 2 through
- p. 3 Scheme 1, compound 8
8, 52% (γ:δ = 2.4:1)
- p. 4 References, footnote 14
Yields and selectivity of compounds 4, 8, 9, 10, and 2 through TFDO oxidation were determined experimentally.
Only the authors can say what is right here.
Judge's note: Read note 14 on page 4 and Scheme 1 on an enlarged render of page 3. Compounds 4 (60%, 1.9:1), 9 (<5%, n.d.), 10 (42%, 1:1.1) and 2 (47%, 1:3.5) carry a [TFDO] line; 8 has only the electrochemical result. The '[TFDO]: <5%' line printed between 8 and 9 belongs to 9, matching the text ('TFDO oxidation failed to produce 9 in meaningful yields'). The TFDO result for 8 may be given only in the Supporting Information, which the note points to and which is not among the files; so this is a question for the authors (is a [TFDO] line for 8 missing from the scheme, or is 8 listed in note 14 by mistake?).
Second check: another model agreed
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Typo The abbreviation is printed "HOBT (H)" in the text (PDF page 1) but "HOBt (H)" in Figure 1B and in the Figure 1C legend.
- p. 1 Body text, right column
NMO (D), TEMPO (G), and HOBT (H) have all proven ineffectual
- p. 2 Figure 1B table, entries 2 and 3 (Yield%)
D as the mediator
- p. 1 p 7448, mediator discussion
HOBT (H) have all proven ineffectual
- p. 1 Figure 1B mediator structure label
HOBt (H)
Judge's note: Page 1 text reads 'HOBT (H) have all proven ineffectual'; Figure 1B structure label and Figure 1C legend on page 2 read 'HOBt (H)'. Cosmetic inconsistency. The other point in this cluster (NMO called ineffectual although 19% exceeds DABCO's 9%) is the same matter as C001 and is covered there.
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Typo Figure 2A heading inside the graphic reads "The 50 scale C–H oxidation of sclareolide (1) enabled the synthesis of 2-oxo-yahazunone (25)."; the unit is missing (caption: "50 g scale"; panel label: "[50-gram scale]").
- p. 3 Figure 2, heading of panel A (inside the graphic)
The 50 scale C–H oxidation of sclareolide (1) enabled the synthesis of 2-oxo-yahazunone (25).
- p. 3 Figure 2 caption
(A) 50 g scale C−H oxidation of sclareolide enabled the synthesis of 2-oxo-yahazunone.
- p. 3 Figure 2, panel A heading inside the figure
The 50 scale C–H oxidation of sclareolide (1)
- p. 3 Figure 2 caption
50 g scale C−H oxidation of sclareolide
Judge's note: Read the heading on an enlarged render of page 3: 'A. The 50 scale C–H oxidation…' with no 'g'. The caption below the figure, the body text and the green label under compound 2 all give 50 g.
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Typo Scheme 1, under compound 4: "A r= 4-ClC6H4" (space misplaced; elsewhere "Ar = 4-ClC6H4"), and the line below reads "4, 56%(δ:β = 3.2:1)" with no space before the parenthesis.
- p. 3 Scheme 1, label under compound 4
A r= 4-ClC6H4
Judge's note: Read on an enlarged render of Scheme 1 (page 3). The label under compound 3 beside it reads 'Ar = 4-ClC6H4' with normal spacing, while that under 4 clearly shows a gap between 'A' and 'r' and none before '='. Cosmetic.
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Typo Reference 5(d) author list: "Crandall, J. K.; Curci, R.; D’Accolti, L.; Fusco, C.; Fusco, C.; D’Accolti, L.; Annese, C." names Fusco and D'Accolti twice.
- p. 4 References, (5)(d)
Crandall, J. K.; Curci, R.; D’Accolti, L.; Fusco, C.; Fusco, C.; D’Accolti, L.; Annese, C.
- p. 4 reference 5(d)
Fusco, C.; Fusco, C.; D’Accolti, L.; Annese, C.
Judge's note: Read on the page 4 image; the repetition is in the published list, not an extraction artefact. It may be deliberate: encyclopedia entries of this kind are often credited to original authors followed by update authors, which would repeat names, but that cannot be checked from the files. Either form could be legitimate.
Second check: none (judge only)