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

Abstract

Tables

Table 1. Required corrections for the original main article.

instance	original	correction	reason
caption of Scheme 4	[…] a) Pd(PPh3)4 (5 mol %), Na2CO3, DMF/H2O, 18 h, 100 °C, 76–99% […].	[…] a) Pd(PPh3)4 (5 mol %), Na2CO3, DMF/H2O, 18 h, 100 °C, 76–97% […].	The percent yields stated for 8b and 8d were erroneous. They should be 96% and 97%, respectively, instead of 99%.
caption of Scheme 6	[…] a) Pd(PPh3)4 (5 mol %), Na2CO3, DMF/H2O, 18 h, 100 °C, 76–99%; b) LAH, AlCl3, THF, 18 h, rt […].	a) Pd(PPh3)4 (5 mol %), Na2CO3, DMF/H2O, 18 h, 100 °C, 70–93%; b) LAH, AlCl3, THF, 18 h, rt, 56–92% […].	The percent yield range of 76–99% for step a was mistakenly copied from the caption of Scheme 4 (step a) without adjustment to compounds 14p–w. Further, the percent yield range for step b was mistakenly not provided.
page 2676	The target compound nobilone (1d) was obtained via TBHP-mediated cyclization of 23 and subsequent TBS deprotection of intermediate 24 with pyridine and HF·pyridine complex [66] in a total yield of 26% over the two steps.	The target compound nobilone (1d) was obtained via TBHP-mediated cyclization of 23 and subsequent TBS deprotection of intermediate 24 with pyridine and HF·pyridine complex [66] in a yield of 58% over the two steps.	—
page 2676	The longest linear sequence was 7 steps, with an overall yield of 5%.	The longest linear sequence was 7 steps. However, the overall yield of 5% for 1d is based on a total of 8 steps required for the synthesis.	—
note in Scheme 7	1d (26% over 2 steps)	1d (58% over 2 steps)	—
Page 2677	[…] and utilized this method for the first total synthesis of the fluorenone natural product nobilone (25) in 8 steps in an overall yield of 2%.	[…] and utilized this method for the first total synthesis of the fluorenone natural product nobilone (25) in an overall yield of 5% in 8 steps.	—

Table 2. Required corrections for the original Supporting Information File 1.

instance	original	correction
several (for example, page S25)	example: K2CO3 (256 mg, 1.55 mmol, 1.00 equiv) and […] were added.	example: K2CO3·1.5H2O (256 mg, 1.55 mmol, 1.00 equiv) and […] were added.
2,7-dihydroxy-4-methoxy-9H-fluorenone (nobilone, 1d)	A solution of crude ketone 24 (777 mg, 1.65 mmol) […]. and pyridine (0.61 mL, 7.59 mmol) […]. Purification by FCC afforded the product as a red solid (275 mg, 1.14 mmol, 26%).	A solution of crude ketone 24 (777 mg) […] and pyridine (0.610 mL, 7.59 mmol) […]. Purification by FCC afforded the product as a red solid (275 mg, 1.14 mmol, 58% over two steps).
4-methoxy-2-phenylbenzaldehyde (8b)	Purification by FCC afforded the product as a red solid (421 mg, 1.98 mmol, 99%).	Purification by FCC afforded the product as a red solid (421 mg, 1.98 mmol, 96%).
4-methoxy-2-phenylbenzaldehyde (8d)	Purification by FCC afforded the product as a red oil (423 mg, 1.99 mmol, 99%).	Purification by FCC afforded the product as a red oil (423 mg, 1.99 mmol, 97%).
5-methoxy-2-phenyl-N-methylbenzyl-amine (9b)	Purification by FCC afforded the product as a yellow oil (178 mg, 0.780 mmol, 72%).	Purification by FCC afforded the product as a yellow oil (178 mg, 0.780 mmol, 75%).
2-(3’,5’-dimethoxyphenyl)-N-methyl-benzylamine (9c)	Purification by FCC afforded the product as a yellow oil (139 mg, 0.696 mmol, 87%).	Purification by FCC afforded the product as a yellow oil (139 mg, 0.541 mmol, 87%).
2-(3’,5’-dimethoxyphenyl)benzonitrile (14c)	Purification by FCC afforded the product as a white solid (187 mg, 0.88 mmol, 88%).	Purification by FCC afforded the product as a white solid (1.39 g, 5.81 mmol, 88%).
2-(4’-methyl-3’-nitrophenyl)-N-(tert-butoxycarbonyl)benzylamine (14o)	Purification by FCC afforded the product as a white solid (416 mg, 1.21 mmol, 67%)	Purification by FCC afforded the product as a white solid (416 mg, 1.21 mmol, 61%)
2-(benzo[d][1,3]dioxol-5-yl)benzonitrile (14p1)	Purification by FCC afforded the product as a white solid (357 mg, 1.74 mmol, 80%)	Purification by FCC afforded the product as a white solid (357 mg, 1.61 mmol, 80%)

Full text

We noticed a number of minor errors in our original publication, including in Supporting Information File 1, that mostly concern the percent yield given for some of the precursors. In addition, there was a larger error related to the yield for the key step of the total synthesis of the title compound nobilone (1d). Finally, it should be noted that the sesquihydrate of K_2_CO_3_ rather than anhydrous K_2_CO_3_ 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 publication are listed in detail below.

Main Article

The required corrections for the original main article are listed in Table 1.

Supporting Information File 1

Compounds

1.3

The required corrections for the original Supporting Information File 1 are listed in Table 2.