SYNTHESIS OF ORGANIC HETEROCYCLES VIA MULTICOMPONENT REACTIONS WITH CYANO TRANSITION-METAL COMPLEXES

Twenty three complexes of the type [M(CO)(5)CNC(NHR(1))C(R(2))(R(3))O] (1-23) have been synthesized by the three-component cycloaddition (3C C) of [M(CN)(CO)(5)](-) (M = Cr, Mo, W) with various isocyanides CNR(1 ) (R(1) = Me, Cy, (t)bu, p-Tol, CH(2)CO(2)Et and CH(2)SO(2)Tol-p) and carbonyl compounds R(2)R(3)C=O (R(2), R(3) = for example, Me, Me; Et, Et; (t)Bu, Me; H, Pr-i; CF3, CF3; [CH2](4); [CH2](5)). Several other m ono- and di-cyano complexes ([Mn-2(CN)(CO)(9)](-), [Fe(CN)(2)Cp(CO)](- ), [Fe(CN)Cp(dppe)], [Ru(CN)Cp(dppe)] and [Co(CN)(2)(dmgH)(2)](-)) als o undergo this obviously general reaction resulting in the 4-amino-oxa zolin-2-ylidene complexes [Mn-2(CO)(9){CNC(NH(t)Bu)C(Me(2))O}] (30), [ MCp{CNC(NH(t)Bu)C(Me(2))O}dppe](BF4) [M = Fe (34), Ru (35)] and [Co(CN )(dmgH)(2){CNC(NHCy)C(Me(2))O}] (36). With amine hydrochloride as the fourth component, however, the 4CC products [Mn-2(CO)(9){CN(H)C(NH(t)B u)C(Ph)NPh}] (29), [Fe(CN)Cp{CN(H)C(NH(t)Bu)C(Ph)NpH}CO] (31) and [Co( CN)(dmgH)(2){CN(H)C(NHR(1))C(R(2))NPh}] [R(1) = Cy, R(2) = Ph (37); p- Tol (38); R(1) = (t)Bu, R(2) = p-Tol (39)] have been obtained on using a molar ratio of cyano complex/organic reagents of 1:2, afforded the bis(heterocyclic) complexes [FeCp(CO){CN(H)C(NH(t)Bu)C(Pr-i)NH}2](PF6) (32), [FeCp(CO){CNC(NH(t)Bu)C(Me(2))O}(2)](BF4) (33) and )(2){CN(H)C( NHCy)C(Ph)NPh}(2)][Co(CN)(2)(dmgH)(2)] (40). To confirm the claimed na ture of the produces, X-ray structure analyses have been carried out o n [Cr(CO)(5){CNC(NHR(1))C(R(2))(R(3))O}] (9) and [Cr(CO)(5){CN(H)C(NHR (1))C(R(2))NR(3)}] (27). Detachment of the carbenoid 4-amino-imiazoles from the complexes [M(CO)5{CN(H)C(NHR)C(Ph)NPh}] [M = W, R = Cy (46); M = Cr, R = (t)Bu (47)] by oxidation with KMnO4/Fe(NO3)3 surprisingly gave the 4-amino-5-hydroxy imidazol-2-ones 48 and 49 which were chara cterized by X-ray analyses.