Conversion of alkynes to cyclic imides and anhydrides using reactive iron carbonyls prepared from Fe(CO)5 and Fe3(CO)12

Microwave‐Assisted Aminocarbonylation of Ynamides by Using Catalytic [Fe3(CO)12] at Low Pressures of Carbon Monoxide

“…[41] With the aim to reduce the amount of nucleophile required, different amines [31c] were tested to generate the catalytically active species "amine-[Fe(CO) 4 ]". [33][34][35]42] By using 1,8-diazabicycloundec-7-ene (DBU) or N,N-diisopropylethylamine (DIPEA) and 2 (1.2 equiv), almost the same yield of 3 was observed (entries 4 and 5, Table 1). The addition of DMF or NH 3 produced a dramatic reduction in reaction yields (entries 7 and 8, Table 1), whereas triethylamine (TEA, 4 equiv) gave 3 in 70 % isolated yield after microwave irradiation for 15 min at 90 8C, in the presence of CO (1.3 bar) and nPrNH 2 (1.2 equiv; entry 6 , Table 1).…”

“…A comparable yield of 3 was also obtained by using [Fe 3 (CO) 12 ] (6 equiv), demonstrating that the complex may act both as the catalyst and the CO source (entry 11, Table 2). [34,35] Finally, applying traditional heating procedures for the aminocarbonylation of 1 at the same CO pressure to that used under microwave heating, a reduction of the overall conversion was observed, as well as the formation of the succinimide byproduct that was never isolated when using microwave dielectric heating (entry 12, Table 2). Microwave irradiation not only dramatically reduces reaction times, but also allows a better conver- 1 [a] [Fe(CO) 5 ] nPrNH 2 (6 equiv) 20 2 [b] -nPrNH 2 (6 equiv) -3 [a] A C H T U N G T R E N N U N G [Fe 3 (CO) 12 ] nPrNH 2 (6 equiv) 50 4 [c] A C H T U N G T R E N N U N G [Fe 3 (CO) 12 ] nPrNH 2 (1 equiv)/DIPEA (4 equiv) 53 5 [c] A C H T U N G T R E N N U N G [Fe 3 (CO) 12 ] nPrNH 2 (1 equiv)/DBU (4 equiv) 52 6 [c] A C H T U N G T R E N N U N G [Fe 3 (CO) 12 ] nPrNH 2 (1 equiv)/TEA (4 equiv) 70 7 [c] A C H T U N G T R E N N U N G [Fe 3 (CO) 12 ] nPrNH 2 (1 equiv)/DMF (4 equiv) 30 8 [c] A C H T U N G T R E N N U N G [b] THF 90 20 min -83 12 [c] THF www.chemeurj.org sion to be observed by using a lower pressure of CO (1.3 vs. 10 bar).…”

“…31 Iron–carbonyl compounds have been increasingly used in organic synthesis in recent years 32–35. In 1997, Periasamy and co‐workers first reported the possibility of using stoichiometric [HFe 3 (CO) 11 ] − for the transformation of alkynes into cyclobutenediones34 and, five years later, they described the use of iron–carbonyl salts for the synthesis of succinimides from alkynes 35. More recently, Beller and co‐workers published a catalytic version of this reaction 36.…”

Iron Complexes in Organic Chemistry

“…In the presence of an excess of a primary amine, this reaction has been applied to the synthesis of cyclic imides [29].…”

Synthesis of heterocycles by carbonylation of acetylenic compounds

“…This complex was detected in the catalytic solution at 240 8C using 1 H NMR techniques. 130 Periasamy et al 131 have shown that the reaction of the alkynes 256 with Fe(CO) 5 In addition, the authors have reported 131 that alkyne -iron carbonyl complexes, prepared from Fe(CO) 5 , NaBH 4 , HOAC, amine, and alkyne or from Fe 3 (CO) 12 , amine and alkyne reagent systems, react with an excess of amine at 25 8C to give the imides 258 in moderate to good yields, after CuCl 2 ·2H 2 O oxidation (Scheme 101).…”