{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,12]],"date-time":"2026-09-12T04:09:00Z","timestamp":1789186140122,"version":"build-2803163510"},"reference-count":25,"publisher":"Pharmaceutical Society of Japan","issue":"9","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Chem. Pharm. Bull.","CHEMICAL &amp; PHARMACEUTICAL BULLETIN"],"published-print":{"date-parts":[[2026,9,12]]},"DOI":"10.1248\/cpb.c26-00375","type":"journal-article","created":{"date-parts":[[2026,9,11]],"date-time":"2026-09-11T22:11:30Z","timestamp":1789164690000},"page":"699-704","source":"Crossref","is-referenced-by-count":0,"title":["Preparation of Highly Functionalized &lt;i&gt;ortho&lt;\/i&gt;-Naphthoquinone Methides and Their Subsequent Intermolecular [4 + 2]-Cycloadditions with Olefins"],"prefix":"10.1248","volume":"74","author":[{"given":"Takaaki","family":"Aijima","sequence":"first","affiliation":[{"name":"Graduate School of Pharmaceutical Sciences, The University of Osaka, 1\u20136 Yamada-oka, Suita, Osaka 565\u20130871, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jin","family":"Tokunaga","sequence":"additional","affiliation":[{"name":"Graduate School of Pharmaceutical Sciences, The University of Osaka, 1\u20136 Yamada-oka, Suita, Osaka 565\u20130871, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Haru","family":"Igusa","sequence":"additional","affiliation":[{"name":"Graduate School of Pharmaceutical Sciences, The University of Osaka, 1\u20136 Yamada-oka, Suita, Osaka 565\u20130871, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yoshinari","family":"Sawama","sequence":"additional","affiliation":[{"name":"Graduate School of Pharmaceutical Sciences, The University of Osaka, 1\u20136 Yamada-oka, Suita, Osaka 565\u20130871, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"163","reference":[{"key":"1","doi-asserted-by":"crossref","unstructured":"1) Schildknecht H., Straub F., Scheidel V., <i>Justus Liebigs Ann. Chem.<\/i>, <b>1976<\/b>, 1295\u20131306 (1976).","DOI":"10.1002\/jlac.197619760716"},{"key":"2","doi-asserted-by":"crossref","unstructured":"2) Olakkengil Shajan S. R., Zia B., Sharma C., Subramanya S. B., Ojha S., <i>Int. J. Mol. Sci.<\/i>, <b>26<\/b>, 12003 (2025).","DOI":"10.3390\/ijms262412003"},{"key":"3","doi-asserted-by":"crossref","unstructured":"3) Lv L., Chen H., Ho C.-T., Sang S., <i>Fitoterapia<\/i>, <b>82<\/b>, 704\u2013708 (2011).","DOI":"10.1016\/j.fitote.2011.02.008"},{"key":"4","doi-asserted-by":"crossref","unstructured":"4) Yu J.-H., Zhai H.-J., Yu Z.-P., Zhang Q.-Q., Ge Y.-X., Zhang Y.-Y., Jiang C.-S., Zhang H., <i>Tetrahedron<\/i>, <b>75<\/b>, 3793\u20133801 (2019).","DOI":"10.1016\/j.tet.2019.05.068"},{"key":"5","doi-asserted-by":"crossref","unstructured":"5) Luo H., Wang Y., Qin Q., Wang Y., Xu J., He X., <i>Bioorg. Chem.<\/i>, <b>110<\/b>, 104800 (2021).","DOI":"10.1016\/j.bioorg.2021.104800"},{"key":"6","doi-asserted-by":"crossref","unstructured":"6) Qiao Y.-F., Takeya K., Itokawa H., Iitaka Y., <i>Chem. Pharm. Bull.<\/i>, <b>38<\/b>, 2896\u20132898 (1990).","DOI":"10.1248\/cpb.38.2896"},{"key":"7","doi-asserted-by":"crossref","unstructured":"7) Itokawa H., Ibraheim Z. Z., Qiao Y.-F., Takeya K., <i>Chem. Pharm. Bull.<\/i>, <b>41<\/b>, 1869\u20131872 (1993).","DOI":"10.1248\/cpb.41.1869"},{"key":"8","doi-asserted-by":"crossref","unstructured":"8) Ho L.-K., Yu H.-J., Ho C.-T., Don M.-J., <i>J. Chin. Chem. Soc.<\/i>, <b>48<\/b>, 77\u201379 (2001).","DOI":"10.1002\/jccs.200100014"},{"key":"9","doi-asserted-by":"crossref","unstructured":"9) Lumb J.-P., Trauner D., <i>Org. Lett.<\/i>, <b>7<\/b>, 5865\u20135868 (2005).","DOI":"10.1021\/ol052472u"},{"key":"10","doi-asserted-by":"crossref","unstructured":"10) Habonimana P., Claessens S., De Kimpe N., <i>Synlett<\/i>, <b>15<\/b>, 2472\u20132475 (2006).","DOI":"10.1055\/s-2006-950441"},{"key":"11","doi-asserted-by":"crossref","unstructured":"11) Lee Y. R., Kim Y. M., <i>Helv. Chim. Acta<\/i>, <b>90<\/b>, 2401\u20132413 (2007).","DOI":"10.1002\/hlca.200790247"},{"key":"12","unstructured":"12) Lee Y. R., Wang X., Kim Y. M., Shim J. J., Kim B. N., Han D. H., <i>Bull. Korean Chem. Soc.<\/i>, <b>28<\/b>, 1735\u20131738 (2007)."},{"key":"13","unstructured":"13) Jung H. W., Oh J. S., Lee S. H., Liang J. L., Kim D. H., Rahman A. F. M. M., Jahng Y., <i>Bull. Korean Chem. Soc.<\/i>, <b>28<\/b>, 1863\u20131866 (2007)."},{"key":"14","unstructured":"14) <i>ortho<\/i>-Naphthoquinone methide (<i>o<\/i>-NQM) is a structural analog of <i>ortho<\/i>-quinone methide (<i>o<\/i>-QM). For a review of <i>o<\/i>-QM, see: Ali K., Mishra P., Kumar A., Reddy D. N., Chowdhury S., Panda G., <i>Chem. Commun.<\/i>, <b>58<\/b>, 6160\u20136175 (2022)."},{"key":"15","doi-asserted-by":"crossref","unstructured":"15) Sawama Y., Shishido Y., Yanase T., Kawamoto K., Goto R., Monguchi Y., Kita Y., Sajiki H., <i>Angew. Chem. Int. Ed.<\/i>, <b>52<\/b>, 1515\u20131519 (2013).","DOI":"10.1002\/anie.201207315"},{"key":"16","doi-asserted-by":"crossref","unstructured":"16) Sawama Y., Kawajiri T., Asai S., Yasukawa N., Shishido Y., Monguchi Y., Sajiki H., <i>J. Org. Chem.<\/i>, <b>80<\/b>, 5556\u20135565 (2015).","DOI":"10.1021\/acs.joc.5b00434"},{"key":"17","doi-asserted-by":"crossref","unstructured":"17) Aijima T., Komagawa S., Akai S., Sawama Y., <i>Adv. Synth. Catal.<\/i>, <b>365<\/b>, 3981\u20133986 (2023).","DOI":"10.1002\/adsc.202300968"},{"key":"18","doi-asserted-by":"crossref","unstructured":"18) Aijima T., Akai S., Sawama Y., <i>Eur. J. Org. Chem.<\/i>, <b>29<\/b>, e202501103 (2026).","DOI":"10.1002\/ejoc.202501103"},{"key":"19","doi-asserted-by":"crossref","unstructured":"19) Abraham E., Cooke J. W. B., Davies S. G., Naylor A., Nicholson R. L., Price P. D., Smith A. D.,<i>Tetrahedron<\/i>, <b>63<\/b>, 5855\u20135872 (2007).","DOI":"10.1016\/j.tet.2007.03.026"},{"key":"20","unstructured":"20) Alternative purification methods, including NH<sub>2<\/sub> silica gel chromatography or recrystallization, were also examined, but neither proved successful."},{"key":"21","unstructured":"21) For the reactions affording <b>17a, 17h, 17i<\/b>, and <b>17j<\/b>, CHCl<sub>3<\/sub>, toluene, and MeCN were evaluated as solvents, and only the highest yields are shown in Table 3. The results obtained using the other solvents are provided in Supplementary Table S1."},{"key":"22","unstructured":"22) Purification by NH<sub>2<\/sub> silica gel column chromatography was also examined, but proved unsuccessful. The isolated yields of <b>17a<\/b>, <b>17i<\/b>, and <b>17j<\/b> obtained after silica gel column chromatography without acetylation are provided in Supplementary Table S1."},{"key":"23","doi-asserted-by":"crossref","unstructured":"23) Total synthesis of rubioncolin B, see: Lumb J. P., Choong K. C., Trauner D., <i>J. Am. Chem. Soc.<\/i>, <b>130<\/b>, 9230\u20139231 (2008).","DOI":"10.1021\/ja803498r"},{"key":"24","doi-asserted-by":"crossref","unstructured":"24) Lai Y., Zhang N., Zhang Y., Chen J.-H., Yang Z., <i>Org. Lett.<\/i>, <b>20<\/b>, 4298\u20134301 (2018).","DOI":"10.1021\/acs.orglett.8b01733"},{"key":"25","doi-asserted-by":"crossref","unstructured":"25) Xu Y., Yang Z., Hu J., Yan J., <i>Synthesis<\/i>, <b>45<\/b>, 370\u2013374 (2013).","DOI":"10.1055\/s-0032-1316838"}],"container-title":["Chemical and Pharmaceutical Bulletin"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.jstage.jst.go.jp\/article\/cpb\/74\/9\/74_c26-00375\/_pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,12]],"date-time":"2026-09-12T03:29:57Z","timestamp":1789183797000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.jstage.jst.go.jp\/article\/cpb\/74\/9\/74_c26-00375\/_article"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,9,12]]},"references-count":25,"journal-issue":{"issue":"9","published-print":{"date-parts":[[2026]]}},"URL":"https:\/\/doi.org\/10.1248\/cpb.c26-00375","relation":{},"ISSN":["0009-2363","1347-5223"],"issn-type":[{"value":"0009-2363","type":"print"},{"value":"1347-5223","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,9,12]]},"article-number":"c26-00375"}}