. 2021 Aug 18;11(8):2101. doi: 10.3390/nano11082101

Table 1.

Screening data of the N-formylation of amine ¹.

Entry	Catalyst	Base	TON ²	Yield ³
1	Fe₃O₄	NaOH	0	N. D. ⁴
2 ⁵	Pd–Fe₃O₄	NaOH	20	55
3 ⁶	Au–Fe₃O₄	NaOH	9	25
4	AuPd–Fe₃O₄	NaOH	23	65
5	AuPd–Fe₃O₄	-	5	14
6 ⁷	AuPd–Fe₃O₄	NaOH	15	43
7	AuPd–Fe₃O₄	Cs₂CO₃	25	69
8	AuPd–Fe₃O₄	CsOH·H₂O	33	90 ⁸
9 ⁹	AuPd–Fe₃O₄	CsOH·H₂O	33	92 (84 ¹⁰)
10 ¹¹	AuPd–Fe₃O₄	CsOH·H₂O	32	89
11 ¹²	AuPd–Fe₃O₄	CsOH·H₂O	15	42 ¹³
12 ¹⁴	AuPd–Fe₃O₄	CsOH·H₂O	89	71

¹ Reaction conditions: 1a (0.20 mmol), catalyst (1.4 mol%), base (3.0 equiv), O₂ (1.0 atm), methanol (1.0 mL), r. t., 18 h. ² Turnover number (TON) = mmol of product/mmol of total metal except Fe. ³ Determined from ¹H NMR spectral analysis through the use of mesitylene as an internal standard. ⁴ N. D. = not detected. ⁵ Pd–Fe₃O₄ (2.8 mol%) was used as a catalyst. ⁶ Au–Fe₃O₄ (2.8 mol%) was used as a catalyst. ⁷ An air balloon was used instead of O₂. ⁸ An average value of three runs (91%, 90%, and 88%). ⁹ Result with 1a (0.50 mmol) in MeOH (2.0 mL). ¹⁰ Yield of isolated product. ¹¹ Result with 1a (1.0 mmol) in MeOH (1.0 mL), 4 h. ¹² Ethanol (1.0 mL) was used instead of methanol. ¹³ Yield of 2a’. ¹⁴ Result with 0.40 mol% of catalyst.