New Strategies for Organic Catalysis: The First Highly Enantioselective Organocatalytic Diels−Alder Reaction
Journal of the American Chemical Society, 2000 · paper · Chemistry
Introduces a strategy for catalysis with small organic molecules, using chiral amines that reversibly form iminium ions with unsaturated aldehydes to mimic Lewis acid activation. It documents the first highly enantioselective organocatalytic Diels-Alder reaction.
Checked: PDF from moodle2.units.it, fetched 5 Oct 2026. Page numbers are those of that PDF.
9 findings
Substance 'the addition of cyclopentadiene to cinnamaldehyde was performed on a 50-mmol scale utilizing catalyst 7 (5 mol %) to afford 12 g of (2S)-8 (99% yield, exo 93% ee)': 50 mmol of adduct 8 (C14H14O, about 198 g/mol) is about 9.9 g, so 12 g, 50 mmol and 99% do not agree.
- p. 2 Body text, left column, paragraph on Table 2 (preparative scale)
scale utilizing catalyst 7 (5 mol %) to afford 12 g of (2S)-8 (99%
- p. 2 left column, scale-up sentence
performed on a 50-mmol scale utilizing catalyst 7 (5 mol %) to afford 12 g of (2S)-8 (99% yield, exo 93% ee)
- p. 2 Results text, preparative scale
50-mmol scale utilizing catalyst 7 (5 mol %) to afford 12 g of (2S)-8 (99% yield
Only the authors can say what is right here.
Judge's note: Sentence read on the page 2 image. Product 8 is drawn in Table 1 as the 1:1 adduct of cinnamaldehyde (C9H8O) and cyclopentadiene (C5H6), i.e. C14H14O; molar mass from standard atomic masses is about 198.3 g/mol. 50 mmol at 99% is about 9.8 g; 12 g corresponds to about 60.5 mmol, about 121% of a 50-mmol scale. Searched the text and footnotes for an explanation: footnote 10 makes the dienophile the limiting reagent (0.5 mmol against 1.5 mmol diene), and nothing says the 50 mmol refers to another reagent or that the product was isolated as a derivative. Which of the three numbers (scale, mass, yield) is misprinted only the authors can say; the Supporting Information is not among the files and might state the actual scale.
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Substance "performed on a 50-mmol scale utilizing catalyst 7 (5 mol %) to afford 12 g of (2S)-8 (99% yield, exo 93% ee)": 50 mmol of adduct 8 (C14H14O, about 198.3 g/mol) is about 9.9 g, so 12 g is more than the theoretical amount and cannot be a 99% yield.
- p. 2 Body text, left column, paragraph on Table 2
5, 89% yield, endo >93% ee, exo >91% ee)
- p. 2 Table 2, entries 4 and 5
99
- p. 2 Body text, Table 2 paragraph
endo >93% ee, exo >91% ee
- p. 2 Table 2, entries 4 and 5
91 (2S)
Only the authors can say what is right here.
Judge's note: Rests on outside knowledge: the molecular weight of adduct 8, taken as the 1:1 cinnamaldehyde-cyclopentadiene aldehyde drawn in Table 1 (C9H8O 132.16 + C5H6 66.10 = 198.26 g/mol). The sentence is on the page as quoted. On that weight 50 mmol is 9.9 g and 99% is 9.8 g; 12 g would be about 60.5 mmol. Possible explanations the files cannot settle: the scale was nearer 60 mmol, or the mass refers to another form of the product (for example a dimethyl acetal formed in MeOH, about 244 g/mol, for which 50 mmol at 99% would be about 12.1 g). The Supporting Information, which is not among the files, would settle it. The other points in this cluster (the '89% yield' for entries 4 and 5, and the strict '>' ee bounds) are recorded under C024 and C017.
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Reference or label Footnote 2(g) prints 'Corey, E. J.; Bo, Y.; Busch-Petersen, J. J. Am. Chem. Soc. 1999, 120, 13000', pairing year 1999 with volume 120, whereas the same list prints '1998, 120, 5943' (2j) and '1999, 121, 7559' (5a).
- p. 1 Footnote 2(g)
Bo, Y.; Busch-Petersen, J. J. Am. Chem. Soc. 1999, 120, 13000.
- p. 1 Footnote 2(j)
Soc. 1998, 120, 5943
- p. 1 Footnote 2(g)
Bo, Y.; Busch-Petersen, J. J. Am. Chem. Soc. 1999, 120, 13000
- p. 1 footnote 2(g)
J. Am. Chem. Soc. 1999, 120, 13000
Only the authors can say what is right here.
Judge's note: Rests on outside knowledge: that J. Am. Chem. Soc. publishes one volume per calendar year (and hence which of year or volume is the misprint). Read the crop: 2(g) is printed as '1999, 120, 13000'. Within the paper's own list volume 120 is 1998 (2j), volume 121 is 1999 (5a, 5b), 119 is 1997 (2h) and 118 is 1996, so the pair 1999/120 is inconsistent with the paper's other entries. The same problem in 2(m) is handled under C003.
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Reference or label Footnote 2(m) prints 'Iwabuchi, Y.; Nakatani, M.; Yokoyama, N.; Hatakeyama, S. J. Am. Chem. Soc. 1999, 120, 10219', pairing year 1999 with volume 120, whereas the same list prints '1999, 121, 7559' (5a) and '1998, 120, 5943' (2j).
- p. 1 Footnote 2(m)
Am. Chem. Soc. 1999, 120, 10219.
- p. 1 Footnote 5(a)
Soc. 1999, 121, 7559
- p. 1 Footnote 2(m)
Am. Chem. Soc. 1999, 120, 10219
Only the authors can say what is right here.
Judge's note: Rests on outside knowledge: that J. Am. Chem. Soc. publishes one volume per calendar year, and which of the year or the volume is the misprint. Read on the page image: 2(m) is printed '1999, 120, 10219'. The paper's other JACS entries give 120 = 1998 and 121 = 1999, so the pair is internally inconsistent. Kept separate from C002, which covers entry 2(g).
Second check: another model agreed
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Reference or label The text cites "(Table 1, 1:1-1.3 endo:exo)" for cyclopentadiene, but Table 1's exo:endo ratios are 2.7:1, 2.3:1, 2.6:1, 3.6:1 and 1.3:1 (no 1:1 entry); the range 1:1 to 1.3:1 is the exo:endo column of Table 2 (1:1, 1:1, 1:1, 1.3:1, 1:1), so the pointer should be to Table 2 (or Tables 1 and 2).
- p. 2 Body text, left column, paragraph on Table 3
exception of cyclopentadiene (Table 1, 1:1-1.3 endo:exo)
- p. 1 Table 1, exo:endo column
2.7:1
- p. 2 Table 2, exo:endo column
1.3:1
- p. 2 column 1, para 3
cyclopentadiene (Table 1, 1:1-1.3 endo:exo)
Judge's note: Read both tables and the sentence on the page images. Table 1 contains only one value in the quoted range (entry 5, catalyst 7, 1.3:1); its other entries run up to 3.6:1 and none is 1:1. Table 2 (cyclopentadiene with catalyst 7) gives exactly 1:1 to 1.3:1. The reviewers' second point, that the direction is reversed, is not upheld: '1:1-1.3 endo:exo' read as 1:1 to 1:1.3 endo:exo equals 1:1 to 1.3:1 exo:endo, so the label agrees with the tables; only the abbreviated form is loose. The defect confirmed is the table pointer.
Second check: another model agreed
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Reference or label Text: '(entries 3-6, 72-89% yield, 1:5-1:11 exo:endo, 83-90% ee)'. In Table 3 the 72% yield and the 1:11 ratio are entry 7 (the acetoxy diene); entries 3-6 have yields 84, 90, 75, 75 and only one ratio (1:5), and the highest yield in entries 3-7 is 90, not 89.
- p. 2 Body text, left column, paragraph on Table 3
of regio- and enantioselectivity (entries 3-6, 72-89% yield, 1:5-
- p. 2 Table 3, entries 3-7, yield and exo:endo columns
72
- p. 2 Body text, Table 3 paragraph
(entries 3-6, 72-89% yield, 1:5-
- p. 2 column 1, para 3 (diene scope)
(entries 3-6, 72-89% yield, 1:5-1:11 exo:endo, 83-90% ee)
Judge's note: Read Table 3 on the image: entry 3 84/--/89, entry 4 90/--/83, entry 5 75/--/90, entry 6 75/1:5/90, entry 7 (OAc) 72/1:11/85. The sentence itself names acetoxy substituents, which only entry 7 has, so the entry range should be 3-7; with that range the ee (83-90) and exo:endo (1:5-1:11) ranges fit, but the yield range is 72-90%, not 72-89% (89 appears in the table only as the ee of entry 3). No footnote or text explains the difference.
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Reference or label Text: 'excellent diastereoselectivity (entries 1, 2, 6, and 7, 5-35:1 endo:exo)', but Table 3 (column 'exo:endo') gives entry 1 as 35:1 and the text earlier says 'entry 1, 75% yield, 35:1 exo:endo'; entries 2, 6 and 7 are 1:14, 1:5 and 1:11 exo:endo.
- p. 2 Body text, left column, paragraph on Table 3
lectivity (entries 1, 2, 6, and 7, 5-35:1 endo:exo)
- p. 2 Table 3, entry 1, exo:endo column
35:1
- p. 2 Body text, Table 3 paragraph
(entries 1, 2, 6, and 7, 5-35:1 endo:exo)
- p. 2 column 1, para 3
entries 1, 2, 6, and 7, 5-35:1 endo:exo
Only the authors can say what is right here.
Judge's note: Read the sentence and Table 3 on the images. As endo:exo, entries 2, 6 and 7 are 14:1, 5:1 and 11:1, and entry 1 is 1:35; the range '5-35:1 endo:exo' therefore labels the entry 1 ratio with the opposite orientation to the table and to the sentence two lines earlier. The table scheme is also headed 'endo adduct' for all entries, so it is not certain from the files whether the text label or the entry 1 table value (35:1 versus 1:35) is the one misprinted; only the authors can say. No explanation in the text or footnotes. (The same sentence continues 'Table 1, 1:1-1.3 endo:exo' for cyclopentadiene, where the tables print 1:1-1.3:1 as exo:endo; noted but not part of this finding.)
Second check: another model agreed
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Wording The text summarises Table 3 as "(entries 3-6, 72-89% yield, 1:5-1:11 exo:endo, 83-90% ee)", but the highest yield in those rows is 90% (entry 4), not 89%, and the 72% yield and 1:11 ratio belong to entry 7, outside the stated entries 3-6.
- p. 2 Body text, left column, paragraph on Table 2
(>75%
- p. 2 Body text, left column, paragraph on Table 2
yield, endo >90% ee, exo >84% ee)
- p. 2 Table 2, entries 1-3
75
- p. 2 Body text, Table 3 paragraph
72-89% yield
Only the authors can say what is right here.
Judge's note: Table 3 read from the page image: yields entry 3 = 84, entry 4 = 90, entry 5 = 75, entry 6 = 75, entry 7 = 72; exo:endo 1:5 (entry 6) and 1:11 (entry 7); ee 89, 83, 90, 90, 85. No row has a yield of 89 (89 is the ee of entry 3). The lower bound 72, the ratio 1:11 and the 'acetoxy' substituent mentioned in the sentence are all entry 7, so the range evidently covers entries 3-7 and its upper yield bound should be 90. Whether the text or the table carries the slip only the authors can say. The other point in this cluster, the strict '>' bounds for Table 2 entries 1-3, is recorded under C017.
Second check: another model agreed
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Wording "(entries 4 and 5, 89% yield, endo >93% ee, exo >91% ee)" gives a single yield of 89% for both entries, but Table 2 entry 4 (Ph) is 99% and only entry 5 (furyl) is 89%.
- p. 2 Body text, Table 2 paragraph
5, 89% yield, endo >93% ee, exo >91% ee)
- p. 2 Table 2, entry 4, yield
99
- p. 2 column 1, para 2
entries 4 and 5, 89% yield, endo >93% ee, exo >91% ee
- p. 2 Table 2 entries 4 and 5
Ph 21 99 1.3:1 93 (2S) 93 (2S)
Judge's note: Table 2 read from the page image: entry 4 yield 99, entry 5 yield 89. Unlike the neighbouring parentheses, the yield carries no '>' sign, so as printed it reads as the yield of both entries and understates entry 4 by ten points; the intended form is presumably a lower bound (≥89%) or the range 89-99%. The strict '>' ee bounds in the same parenthesis (93, 93 and 93, 91 in the table) are recorded under C017.
Second check: another model agreed
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10 minor (typos and the like; most checked by the judge only)
Typo Footnote 2(j) prints the author name as 'Wnag, X.-C.' ('Yang, D.; Wong, M.-K.; Yip, Y.-C.; Wnag, X.-C.; Tang, M.-W.; ...'); evidently 'Wang'.
- p. 1 Footnote 2(j)
Wnag, X.-C.
- p. 1 footnote 2(j)
Y.-C.; Wnag, X.-C.; Tang, M.-W.
- p. 1 Footnote 3
Riant, O.; Kagan, B.
- p. 1 Footnote 5(c)
Isihara, K.
Judge's note: Visible on the page image, not an extraction artefact: 'Wnag' is printed. A letter transposition of Wang (the spelling 'Wang' appears in 2(k) for a different author). The 'Kagan, B.' and 'Isihara' points mentioned by one reviewer are judged under C008 and C005.
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Typo Footnotes 5(c) and 5(d) print the first author as 'Isihara, K.' ('(c) Isihara, K.; Yamamoto, H. J. Am. Chem. Soc. 1994, 116, 1561. (d) Isihara, K.; Kurihara, H.; Yamamoto, H.'); reviewers say the name is Ishihara.
- p. 1 Footnote 5(c)
(c) Isihara, K.;
- p. 1 Footnote 5(d)
(d) Isihara, K.; Kurihara,
- p. 1 Footnote 5(c), 5(d)
Isihara, K.;
- p. 1 footnote 5(d)
Isihara, K.; Kurihara
Only the authors can say what is right here.
Judge's note: Rests on outside knowledge: that the author of the cited Yamamoto-group papers spells the name 'Ishihara'. The page image shows 'Isihara' in both entries. Nothing in the paper itself gives the other spelling, and 'Isihara' is a possible romanisation, so this cannot be settled from the files; raised as a query.
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Typo Footnote 2 prints 'Bayliss-Hillman reaction: (m) Iwabuchi, Y.; ...'; reviewers say the reaction name is spelled 'Baylis-Hillman'.
- p. 1 Footnote 2, before (m)
Bayliss-Hillman
- p. 1
Bayliss-Hillman reaction: (m) Iwabuchi
Only the authors can say what is right here.
Judge's note: Rests on outside knowledge: that the reaction is named after Baylis (single s). The page image shows 'Bayliss-Hillman' as quoted. The paper offers no other spelling to compare with.
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Typo Footnote 2(c) prints '(c) Agami, C.; Meyneir, F.; Puchot, C. Tetrahedron 1984, 40, 1031'; reviewers say the co-author's name is misspelled.
- p. 1 Footnote 2(c)
Meyneir, F.;
- p. 1 Footnote 2(c)
Meyneir, F.
- p. 1 footnote 2(c)
Meyneir, F.; Puchot, C.
- p. 1
Meyneir, F.; Puchot, C. Tetrahedron 1984
Only the authors can say what is right here.
Judge's note: Rests on outside knowledge: the true spelling of the co-author of the cited Tetrahedron 1984 paper. The reviewers themselves disagree on it (Meynier or Meyniel), which shows it cannot be settled from memory. The page image does print 'Meyneir', an unusual letter order, so it is worth a query to the authors.
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Typo Footnote 3 prints 'Riant, O.; Kagan, B. Tetrahedron Lett. 1989, 30, 7403' while footnote 4(b) prints 'Kagan, H. B.; Riant, O. Chem. Rev. 1992, 92, 1007': the same author with initials 'B.' and 'H. B.'.
- p. 1 Footnote 3
Riant, O.; Kagan, B. Tetrahedron Lett. 1989, 30, 7403.
- p. 1 Footnote 4(b)
(b) Kagan, H.
- p. 1 Footnote 3
Riant, O.; Kagan, B. Tetrahedron Lett. 1989, 30, 7403
- p. 1 Footnote 4(b)
Kagan, H.
Judge's note: Both entries read on the page image. Same co-author pair (Riant and Kagan) on the same subject, cited with different initials within the paper; the first initial is missing in footnote 3. Internal inconsistency, no outside fact needed.
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Typo Footnote 4 reads 'see: Oppolzer, W. In Comprehensive Organic Synthesis; ... Vol. 5. (b) Kagan, H. B.; ... (c) Oh, T.; ... (d) Dias, L. C.': the first entry carries no '(a)' label although (b)-(d) follow.
- p. 1 Footnote 4
chiral Lewis acids, see: Oppolzer, W. In
Judge's note: Checked on the page image: no '(a)' is printed before Oppolzer, while footnotes 1, 2 and 5 all begin their lettered entries with (a).
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Typo Table footnote a (Tables 1, 2 and 3) prints 'Bodman Γ-TA or β-PH column', with a capital gamma beside a lower-case beta.
- p. 1 Table 1, footnote a
Bodman Γ-TA or
- p. 2 Table 2, footnote a
Bodman Γ-TA or
Judge's note: The crops show a capital Γ next to an italic lower-case β in the footnotes of the tables. Whether the column designation should be lower-case γ (or the letter G) depends on the manufacturer's product name, which is not in the files; the capital may be a deliberate rendering of the trade designation. Mixed case is real but either form could be legitimate.
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Typo Footnote 1 prints 'Yamamoto, H., Eds; Springer' and 'Noyori, R., Ed; Wiley' without the period, while the same footnote prints 'Ojima, I., Ed.; VCH' and footnote 4 'Trost, B. M., Ed.; Pergamon Press'.
- p. 1 footnote 1
Yamamoto, H., Eds; Springer
- p. 1 footnote 1
Noyori, R., Ed; Wiley
Judge's note: Read on the crop of the footnotes: entries 1(a) and 1(b) lack the period after Eds/Ed; 1(c) and footnote 4 have it. Punctuation inconsistency within one footnote.
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Typo Strict '>' bounds in the text equal the lowest tabulated values: "entries 1 and 2, >80%" (Table 1 entry 2 = 80), "entries 3 and 4, >82% yield" (entry 4 = 82), ">75% yield, endo >90% ee, exo >84% ee" (Table 2 entries 1-3 minima 75, 90, 84) and "endo >93% ee, exo >91% ee" (entries 4-5: 93, 93 and 93, 91); each should be '≥'.
- p. 2 Body text, first lines of left column
(entries 1 and 2, >80%, 2.3-2.7:1
- p. 1 Table 1, entry 2, yield
80
- p. 2 column 1, para 1
entries 1 and 2, >80%
- p. 2 column 1, para 1
entries 3 and 4, >82%
Judge's note: Checked on the page image and crop that the printed sign is a plain '>' in every case, not '≥'. Table 1 yields: 81, 80, 92, 82. Table 2 entries 1-3: yield 75, 92, 81; endo ee 90, 90, 93; exo ee 86, 86, 84; entries 4-5: endo 93, 93; exo 93, 91. Every bound is attained exactly, so the strict inequalities are literally untrue, but this is a consistent loose use of '>' for 'at least' and misleads nobody by more than the boundary case. This cluster is taken as the home for all the strict-inequality points (C018, C023 are duplicates). The R1-versus-R notation point also raised here is handled in C022.
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Typo The text calls the dienophile substituent "R1" ("olefin substituent (R1 = Me, Pr, i-Pr, entries 1-3)"), whereas Table 2 and its scheme label it "R"; in Scheme 1, R1 and R2 are the substituents on the catalyst amine nitrogen.
- p. 2 Body text, left column, paragraph on Table 2
contribution of the olefin substituent (R1 ) Me, Pr, i-Pr, entries
- p. 2 Table 2, scheme and column header
R
- p. 2 Body text, Table 2 paragraph
(R1 ) Me, Pr, i-Pr, entries
- p. 2 Table 2 header
entry R time (h)
Judge's note: Seen on the page images: the body text prints R with subscript 1; the Table 2 column header and scheme print plain R; Scheme 1 on page 1 uses R1/R2 (superscripts) for the amine and iminium nitrogen substituents. The ') ' in the text layer is the '=' sign and is an extraction artefact, not part of the finding. Meaning is clear from context, so this is a cosmetic notation inconsistency.
Second check: none (judge only)