A New Palladium Precatalyst Allows for the Fast Suzuki−Miyaura Coupling Reactions of Unstable Polyfluorophenyl and 2-Heteroaryl Boronic Acids
Journal of the American Chemical Society, 2010 · paper · Chemistry
Develops a palladium precatalyst that forms the active species quickly under mild conditions where boronic acids decompose slowly. It enables Suzuki–Miyaura couplings of unstable polyfluorophenyl and 2-heteroaryl boronic acids at room temperature or 40 °C in excellent yields.
3 findings
Reference or label Ref. 7 says "2-heterocyclic MIDA boronates were successfully employed for SMCs (See Ref. 4a)", but Ref. 4a is Antonow et al., J. Med. Chem. 2010, cited under couplings of 2,6-difluorophenylboronic acid. The MIDA-boronate paper is Ref. 5a (Knapp, Gillis, Burke, JACS 2009).
- p. 4 Reference 7
2-heterocyclic MIDA boronates were successfully employed for SMCs (See Ref. 4a)
- p. 4 Reference 4a / 5a
(a) Antonow D, et al. J. Med. Chem. 2010; 53:2927.
- p. 4 Reference 7
(See Ref. 4a)
- p. 4 Reference 4a
Antonow D, et al. J. Med. Chem. 2010; 53:2927.
Judge's note: On page 4, Ref. 4 is introduced as "examples for the coupling of 2,6-difluorophenylboronic acid with vinyl triflates and aryl bromides", and 4a is Antonow. Ref. 5a is Knapp DM, Gillis EP, Burke MD, J. Am. Chem. Soc. 2009; 131:6961. The cross-reference evidently should point to 5a.
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Reference or label The Table 3 caption ends with superscript b ("...aryl and benzyl chlorides and aryl bromides.b"), but the table's only footnote is labelled a ("aArX (1 mmol), ArB(OH)2 (1.5 mmol), 13 (2 mol %)..."). No footnote b exists, and footnote a is never called out.
- p. 12 Table 3 caption and footnote
aryl and benzyl chlorides and aryl bromides.b
- p. 12 Table 3 caption and footnote
aryl bromides.b
- p. 12 Table 3 footnote
ArX (1 mmol), ArB(OH)2 (1.5 mmol), 13 (2 mol %)
- p. 12 Table 3 footnote
aArX (1 mmol), ArB(OH)2 (1.5 mmol)
Judge's note: On page 12 I checked the caption and the table body. The caption carries superscript b, and the only footnote below the table is a, which gives the reaction conditions. The body has no a or b markers. Table 1 on page 10 uses the same conditions footnote with marker a on its caption, so the Table 3 marker is evidently wrong.
Second check: another model agreed
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Wording Page 3 names "2-chlorobenzoxindole" as the substrate behind product 22b, but Table 3 draws 22b as a 2-(N-Boc-pyrrol-2-yl)benzoxazole, so the substrate is 2-chlorobenzoxazole.
- p. 3 Paragraph on heteroaryl boronic acids
2-chlorobenzoxindole as well as 2-chloroacetanilide
- p. 12 Table 3, product 22b
22b
- p. 3 heteroaryl paragraph
2-chlorobenzoxindole
- p. 12 Table 3, compound 22b
22b X = Cl, 40 °C, 2 h 91%
Judge's note: In Table 3 on page 12, 22b is drawn as a benzo-fused ring with N and O (a benzoxazole) carrying an N-Boc-pyrrol-2-yl group at C2, with conditions X = Cl, 40 °C, 2 h, 91%. No oxindole appears. The page 3 sentence lists 22b among the products made from the named substrates, so the name does not match the structure. The structure in the table is correct; only the name in the text is wrong.
Second check: another model agreed
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8 minor (typos and the like; most checked by the judge only)
Reference or label Ref. 1a reads "Miyaura N, Yamada K, Suzuki A. Tetrahedron Lett. 1979; 36:3427." The 36 appears to be the issue number, not the volume, and the start page appears to be 3437.
- p. 4 Reference 1a
Tetrahedron Lett. 1979; 36:3427.
- p. 4 Reference 1a
Tetrahedron Lett. 1979; 36:3427
Only the authors can say what is right here.
Judge's note: Rests on outside knowledge: that the Miyaura–Yamada–Suzuki paper is Tetrahedron Lett. 1979, vol. 20, issue 36, pp. 3437–3440. The page 4 image does read "1979; 36:3427". The files contain nothing to check the citation against.
Second check: another model agreed
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Wording Page 2 says "Heteroaromatic compounds readily underwent the SMC to form the desired products in excellent yields", but Table 1 lists heteroaryl products 15d (pyrazine, X = Cl) at 77% and 17a (3-furyl, X = Br, 3 mol%) at 45%.
- p. 2 Last paragraph
Heteroaromatic compounds readily underwent the SMC to form the desired products in excellent yields
- p. 10 Table 1, 15d and 17a
45%
- p. 10 Table 1, 15d and 17a
X = Cl 77%
Only the authors can say what is right here.
Judge's note: I checked the page 2 text and Table 1 on page 10. The heteroaryl entries are 15c 99%, 15d 77%, 16a 95% and 17a 45%b. The sentence does add that five-membered chloro- or bromoheteroarenes "with multiple heteroatoms" were problematic. That caveat does not cover 17a, whose 3-furyl ring has one heteroatom, and it does not cover the pyrazine 15d either. Calling all of these "excellent" overstates the table, so this is a wording point.
Second check: another model agreed
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Typo Misspelling on page 3: "is a prerequesite for the successful coupling" should read "prerequisite".
- p. 3 Paragraph before summary
is a prerequesite for the successful
- p. 3 Results, paragraph on fast generation of XPhosPd(0)
prerequesite
- p. 3 Acknowledgments
assistence
Judge's note: The page 3 image shows "prerequesite". One reviewer note in this cluster also mentions "assistence"; that word is judged separately under C005.
Second check: none (judge only)
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Typo Misspelling in the Acknowledgments: "Dr. Jaclyn Henderson for assistence with some experiments" should read "assistance".
- p. 3 Acknowledgments
assistence with some experiments
- p. 3 Acknowledgments
for assistence with some experiments
- p. 3
Dr. Jaclyn Henderson for assistence with some experiments
Judge's note: The Acknowledgments on page 3 show "assistence".
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Typo Reference 5 uses the label "(c)" twice; the Tyrell E, Brookes P entry should be (d).
- p. 4 Reference 5
45:3484. (c) Tyrell E
- p. 4 Reference 5
Angew. Chem. Int. Ed. 2006; 45:3484. (c) Tyrell E,
- p. 4 Reference 5
(c) Tyrell E,
Judge's note: The duplicate label is visible in the page 4 image.
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Typo Ref. 1 shows a missing space: "653:54.(c) Miyaura".
- p. 4 Reference 1
653:54.(c) Miyaura
Judge's note: The page 4 image shows no space before (c).
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Typo Reference 5 uses the label (c) twice: "(c) Billingsley KL, Anderson KW, Buchwald SL..." and "(c) Tyrell E, Brookes P. Synthesis. 2003:469." The second should be (d).
- p. 4 Reference 5
(c) Tyrell E, Brookes P. Synthesis. 2003:469.
- p. 4
(c) Tyrell E,
Judge's note: The page 4 image shows Ref. 5 with entries (a), (b), (c), (c).
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Typo Table 1 title reads "Coupling of polyfluoroboronic acids", omitting 'phenyl' (polyfluorophenylboronic acids).
- p. 10 Table 1 caption
Coupling of polyfluoroboronic acids to aryl chlorides
- p. 10 Table 1 title
Coupling of polyfluoroboronic acids
Judge's note: Seen in the page 10 image. The text and Table 2 use 'polyfluorophenylboronic acids'.
Second check: none (judge only)