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Bull.","CHEMICAL &amp; PHARMACEUTICAL BULLETIN"],"published-print":{"date-parts":[[2025,4,23]]},"DOI":"10.1248\/cpb.c24-00837","type":"journal-article","created":{"date-parts":[[2025,4,22]],"date-time":"2025-04-22T22:06:35Z","timestamp":1745359595000},"page":"396-400","source":"Crossref","is-referenced-by-count":0,"title":["Unexpected Surprise in the Reactions of Acetals and Trialkylsilyl Chloride (R&lt;sub&gt;3&lt;\/sub&gt;SiCl): Efficient Deprotection of Aromatic Acyclic Acetals"],"prefix":"10.1248","volume":"73","author":[{"given":"Muthu","family":"Karuppasamy","sequence":"first","affiliation":[{"name":"SANKEN, Osaka University, 8\u20131 Mihogaoka, Ibaraki, Osaka 567\u20130047, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ishani Uditha","family":"Wedage","sequence":"additional","affiliation":[{"name":"SANKEN, Osaka University, 8\u20131 Mihogaoka, Ibaraki, Osaka 567\u20130047, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mohamed S. H.","family":"Salem","sequence":"additional","affiliation":[{"name":"SANKEN, Osaka University, 8\u20131 Mihogaoka, Ibaraki, Osaka 567\u20130047, Japan"},{"name":"Pharmaceutical Organic Chemistry Department, Faculty of Pharmacy, Suez Canal University, Ismailia 41522, Egypt"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Koji","family":"Morimoto","sequence":"additional","affiliation":[{"name":"College of Pharmaceutical Sciences, Ritsumeikan University, 1\u20131\u20131 Nojihigashi, Kusatsu, Shiga 525\u20138577, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Shinobu","family":"Takizawa","sequence":"additional","affiliation":[{"name":"SANKEN, Osaka University, 8\u20131 Mihogaoka, Ibaraki, Osaka 567\u20130047, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hiromichi","family":"Fujioka","sequence":"additional","affiliation":[{"name":"SANKEN, Osaka University, 8\u20131 Mihogaoka, Ibaraki, Osaka 567\u20130047, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"163","reference":[{"doi-asserted-by":"crossref","unstructured":"1) Wuts P. G. M., Greene T. W., \u201cGreen\u2019s Protective Groups in Organic Synthesis,\u201d 4th ed., John Wiley &amp; Sons, Inc., Hoboken, NJ, 2006, p. 431.","key":"1","DOI":"10.1002\/0470053488"},{"doi-asserted-by":"crossref","unstructured":"2) Jung M. E., Andrus W. A., Ornstein P. L., <i>Tetrahedron Lett.<\/i>, <b>18<\/b>, 4175\u20134178 (1977).","key":"2","DOI":"10.1016\/S0040-4039(01)83458-4"},{"doi-asserted-by":"crossref","unstructured":"3) Ukaji Y., Koumoto N., Fujisawa T., <i>Chem. Lett.<\/i>, <b>18<\/b>, 1623\u20131626 (1989).","key":"3","DOI":"10.1246\/cl.1989.1623"},{"unstructured":"4) Reference 3 reports that the deprotection of 2-methyl-2-phenethyl dioxolane with TMSCl in THF yielded 4-phenyl-2-butanone in only 6% yield, even after 93 h.","key":"4"},{"doi-asserted-by":"crossref","unstructured":"5) Yao Y., Zhao G., Hamze A., Alami M., Provot O., <i>Eur. J. Org. Chem.<\/i>, <b>2020<\/b>, 5775\u20135779 (2020).","key":"5","DOI":"10.1002\/ejoc.202000979"},{"doi-asserted-by":"crossref","unstructured":"6) Fujioka H., <i>Chem. Pharm. Bull.<\/i>, <b>68<\/b>, 907\u2013945 (2020).","key":"6","DOI":"10.1248\/cpb.c20-00178"},{"doi-asserted-by":"crossref","unstructured":"7) Fujioka H., Okitsu T., Sawama Y., Murata N., Li R., Kita Y., <i>J. Am. Chem. Soc.<\/i>, <b>128<\/b>, 5930\u20135938 (2006).","key":"7","DOI":"10.1021\/ja060328d"},{"doi-asserted-by":"crossref","unstructured":"8) Ohta R., Matsumoto N., Ueyama Y., Kuboki Y., Aoyama H., Murai K., Arisawa M., Maegawa T., Fujioka H., <i>J. Org. Chem.<\/i>, <b>83<\/b>, 6432\u20136443 (2018).","key":"8","DOI":"10.1021\/acs.joc.8b00675"},{"unstructured":"9) Initially, benzaldehyde dimethyl acetal was employed as the substrate; however, due to its volatile nature, some was lost during the concentration and drying processes. Subsequently, <i>para<\/i>-methoxy benzaldehyde dimethyl acetal was selected as an alternative, but its high reactivity led to its conversion into aldehyde even during TLC. Ultimately, <i>para<\/i>-chloro benzaldehyde dimethyl acetal was identified as the optimal model substrate.","key":"9"},{"unstructured":"10) Completion of the reaction was checked by TLC.","key":"10"},{"unstructured":"11) TMSCl, when the reagent bottle is first opened, is considered fresh TMSCl.","key":"11"},{"unstructured":"12) The literature [Berliner M. A., Belecki K., <i>J. Org. Chem.<\/i>, <b>70<\/b>, 9618\u20139621 (2005)] shows that the hydrogen atom of O-CH-Cl appears at <i>\u03b4<\/i> 5.43 ppm.","key":"12"},{"unstructured":"13) The NMR chart of the reaction of <b>1a<\/b> did not show any CH3Cl. This is because it has a low boiling point of \u201324.2\u00b0C and was removed from the reaction solution. On the other hand, chloroethane, with a boiling point of 12.3\u00b0C, and 2-chloropropane, with a boiling point of 35.7\u00b0C, were observed by NMR of the reaction mixture of diethyl acetal <b>1h<\/b> or diisopropyl acetal <b>1i<\/b> (see Supplementary Materials). In addition, in the case of diisopropyl acetal <b>1i<\/b>, a signal corresponding to Cl-CH-OiPr acetal, formed by the attack of the chloride anion on the benzylic carbon, was also observed as a minor component. This is believed to be due to the steric hindrance of the isopropyl group, indicating that the reaction of diisopropyl acetal <b>1i<\/b> proceeded in 2 ways: route <i>via<\/i> a as the major route and route <i>via<\/i> b as the minor route.","key":"13"},{"doi-asserted-by":"crossref","unstructured":"14) Dong J.-L., Yu L.-S.-H., Xie J.-W., <i>ACS Omega<\/i>, <b>3<\/b>, 4974\u20134985 (2018).","key":"14","DOI":"10.1021\/acsomega.8b00159"},{"doi-asserted-by":"crossref","unstructured":"15) Lee S. H., Lee J. H., Yoon C. M., <i>Tetrahedron Lett.<\/i>, <b>43<\/b>, 2699\u20132703 (2002).","key":"15","DOI":"10.1016\/S0040-4039(02)00387-8"},{"doi-asserted-by":"crossref","unstructured":"16) Williams D. B. G., Lawton M. C., <i>Green Chem.<\/i>, <b>10<\/b>, 914\u2013917 (2008).","key":"16","DOI":"10.1039\/b805748f"},{"doi-asserted-by":"crossref","unstructured":"17) De S. K., Gibbs R. A., <i>Tetrahedron Lett.<\/i>, <b>45<\/b>, 8141\u20138144 (2004).","key":"17","DOI":"10.1016\/j.tetlet.2004.09.060"},{"doi-asserted-by":"crossref","unstructured":"18) Barbasiewicz M., Ma\u0327kosza M., <i>Org. Lett.<\/i>, <b>8<\/b>, 3745\u20133748 (2006).","key":"18","DOI":"10.1021\/ol0613113"},{"doi-asserted-by":"crossref","unstructured":"19) Karimi B., Hazarkhani H., Maleki J., <i>Synthesis<\/i>, <b>2005<\/b>, 279\u2013285 (2005).","key":"19","DOI":"10.1055\/s-2004-837291"},{"doi-asserted-by":"crossref","unstructured":"20) Ranu B. C., Jana R., Samanta S., <i>Adv. Synth. Catal.<\/i>, <b>346<\/b>, 446\u2013450 (2004).","key":"20","DOI":"10.1002\/adsc.200303154"}],"container-title":["Chemical and Pharmaceutical Bulletin"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.jstage.jst.go.jp\/article\/cpb\/73\/4\/73_c24-00837\/_pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,4,26]],"date-time":"2025-04-26T03:26:13Z","timestamp":1745637973000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.jstage.jst.go.jp\/article\/cpb\/73\/4\/73_c24-00837\/_article"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,4,23]]},"references-count":20,"journal-issue":{"issue":"4","published-print":{"date-parts":[[2025]]}},"URL":"https:\/\/doi.org\/10.1248\/cpb.c24-00837","relation":{},"ISSN":["0009-2363","1347-5223"],"issn-type":[{"type":"print","value":"0009-2363"},{"type":"electronic","value":"1347-5223"}],"subject":[],"published":{"date-parts":[[2025,4,23]]},"article-number":"c24-00837"}}