Cyclotrimerisation of isocyanates catalysed by low-coordinate Mn(ii) and Fe(ii) m-terphenyl complexes

Abstract

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Isocyanurate Formation During Oxazolidinone Synthesis from Epoxides and Isocyanates Catalysed by a Chromium(Salphen) Complex

“…groups at the para-position, chromium(salphen) complex 10 was found to catalyse the formation of both oxazolidinones and isocyanurates (perhydro-1,3,5-triazine-2,4,6-triones) 12 ( Figure 2) (Table3,e ntries 3-5). [18] Isocyanurates have previously been prepared by the cyclotrimerisation of isocyanates catalysed by species including organotin [19] and organozinc compounds, [20] copper and nickel halides [21] and palladium, [22] magnesium, [23] and iron complexes. [18] Isocyanurates have previously been prepared by the cyclotrimerisation of isocyanates catalysed by species including organotin [19] and organozinc compounds, [20] copper and nickel halides [21] and palladium, [22] magnesium, [23] and iron complexes.…”

“…Isocyanurates are knownt oe nhance the physical properties of polyurethanes and coating materials, [17] typically by increasing their flame retardation and filming characteristics, and commercialp roducts containing polymerici socyanurates have increased chemical andt hermal resistance. [23] The formation of isocyanurates 12 a-c was much less important when the competing reactionw as between epichlorohydrin 1c andi socyanates than when styreneo xide 1a was used. [23] The formation of isocyanurates 12 a-c was much less important when the competing reactionw as between epichlorohydrin 1c andi socyanates than when styreneo xide 1a was used.…”

Iron(II)‐Catalyzed Hydrophosphination of Isocyanates

“…Herein, we report the first transition metal catalyzed hydrophosphination of isocyanates,which affords phosphinodicarboxamides by an unprecedented catalytic double insertion of isocyanates into the PÀHbond of the phosphine.T he reaction between organic isocyanates and diphenylphosphine in the presence of catalytic amounts of (2,6-Mes 2 C 6 H 3 ) 2 Fe [8] (1;M es = 2,4,6-Me 3 C 6 H 2 )o r( 2,6-Tmp 2 C 6 H 3 ) 2 Fe(THF) [9] (2; Tmp = 2,4,5-Me 3 C 6 H 2 )p roduces the mono-(3)a nd/or diinsertion (4)p roducts,w here one and two isocyanate units, respectively,h ave inserted into the PÀHb ond (Scheme 1). This result is remarkable since diinsertion processes are incredibly rare.…”

“…When the reaction was performed with nHexNCO,the hydrophosphination competed with the cyclotrimerization reaction, leading to amixture of [nHexNCO] 3 , [9] [Ph 2 PC(=O)N(H)nHex] (3e), and [Ph 2 PC(=O)N(nHex)-C(=O)N(H)nHex] (4e)( Table 1, entries [10][11][12]. When the reaction was performed with nHexNCO,the hydrophosphination competed with the cyclotrimerization reaction, leading to amixture of [nHexNCO] 3 , [9] [Ph 2 PC(=O)N(H)nHex] (3e), and [Ph 2 PC(=O)N(nHex)-C(=O)N(H)nHex] (4e)( Table 1, entries [10][11][12].…”

Organic Transformations Catalysed by Low-Coordinate m-Terphenyl Complexes

“…In addition to stoichiometric reactivity towards small molecules, these complexes are efficient precatalysts for the cyclotrimerisation of isocyanates ( Figure 1); they exhibit high selectivity and allow the formation of mixed species through cross-coupling reactions [5]. Significantly, we have also demonstrated the catalysis of hydrophosphination reactions that produce mono-(M) or diinsertion (D) phosphinocarboxamide products selectively (Figure 1) [2].…”