Correction: Synthesis of highly substituted fluorenones via metal-free TBHP-promoted oxidative cyclization of 2-(aminomethyl)biphenyls. Application to the total synthesis of nobilone

• Ilya A. P. Jourjine,
• Lukas Zeisel,
• Jürgen Krauß and
• Franz Bracher

Beilstein J. Org. Chem. 2024, 20, 170–172, doi:10.3762/bjoc.20.16

• Ilya A. P. Jourjine Lukas Zeisel Jurgen Krauss Franz Bracher Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians University of Munich, Butenandtstraße 5–13, 81377 Munich, Germany 10.3762/bjoc.20.16 Keywords: cross-dehydrogenative coupling; cyclization; fluorenones; nobilone

• title compound nobilone (1d). Finally, it should be noted that the sesquihydrate of K2CO3 rather than anhydrous K2CO3 was used. In the original publication, we stated that the TBHP-mediated cyclization of compound 23 (929 mg, 1.96 mmol) to give compound 24 and the subsequent deprotection of crude

• compound 24 to give the title compound 1d (275 mg, 1.14 mmol) was achieved in a percent yield of 26% over two steps. However, this does not match the amounts of substance given for amine 23 and nobilone (1d), respectively. The yield should be 58% instead of 26%. All required corrections for the original

Synthesis of highly substituted fluorenones via metal-free TBHP-promoted oxidative cyclization of 2-(aminomethyl)biphenyls. Application to the total synthesis of nobilone

• Ilya A. P. Jourjine,
• Lukas Zeisel,
• Jürgen Krauß and
• Franz Bracher

Beilstein J. Org. Chem. 2021, 17, 2668–2679, doi:10.3762/bjoc.17.181

• groups for phenols) and was further utilized in the first total synthesis of the natural product nobilone. Keywords: cross-dehydrogenative coupling; cyclization; fluorenones; nobilone; total synthesis; Introduction Fluorenones are an important class of aromatic natural products, and since the

• identified (Scheme 1). However, a couple of structure assignments had to be revised, mostly based on results from total syntheses [4][5]. Numerous biological activities have been reported for natural fluorenones, e.g., antioxidative properties of dendroflorin (1c) and nobilone (1d) [6], antiischemic activity

• -radical reagents [62]. An extremely poor yield was further obtained with methylenedioxy substrate 15p. Our application of this new protocol to the first total synthesis of the natural product nobilone (1d) is depicted in Scheme 7. The commercially available phenol 16 was TBS-protected to give compound 17