Reactions of Aziridine, Thiirane, and Oxirane With Isocyanide Ligands In Complexes of Palladium(II) and Platinum(II) - Syntheses of Neutral 5-membered Cyclic Diaminocarbene, Aminothiocarbene and Aminooxycarbene Compounds

Aziridine is observed to react spontaneously in THF at room temperature or below with the coordinated RNC ligand in each of the neutral isocyanide complexes cis-Cl2(L)M(CNR) (M = Pd, R = t-Bu, p-MeOC6H4L = PPh3PMe2Ph; M = Pt, R = p-MeOC6H4p-MeC6H4L = PPh3) to form the corresponding five-membered cyclic diaminocarbene complexes cis-Cl2(L)M- [CN(R)CH2CH2NH]. Aziridine reacts also with the bis(isocyanide) complexes cis-Cl2Pd(CNR)2(R = t-Bu, p-MeOQH4), converting one (R = t-Bu) or two (R = p-MeOC6H4) isocyanide ligands to cyclic carbenes. Reactions between thiirane and Pd(II)-isocyanide complexes such as cis-Cl2(L)Pd(CNC6H4-p-OMe) (L = PPh3PMe2Ph) in THF at room temperature yield the corresponding cyclic aminothiocarbene derivatives cis-Cl2(L)Pd[CN(R)CH2CH2S]. Thiirane reacts with cis-Cl2Pd(CNC6Hn)2to give the mixed isocyanide-aminothiocarbene derivative cis-Cl2(C6H11NC)Pd[CN(C6H11)CH2CH2S]. Oxirane alone is not reactive toward Pd(II)- and Pt(II)-isocyanide complexes. However, in the presence of NaCl, oxirane is observed to react in 2-chloroethanol with Pt(II)-isocyanide complexes such as cis-Cl2(Ph3P)Pt(CNC6H4-p-OMe) and trans-[(PPh3)2Pt(CNC6H4-p- OMe)Cl]BF4to form the corresponding five-membered cyclic M=CN(R)CH2CH2O aminooxycarbene complexes. Reaction of cis-Cl2Pt(CNC6H4-p-OMe)2with oxirane in the presence of Cl-ions produces the mixed isocyanide-aminooxycarbene complex cis-Cl2(p-MeOC6H4NC)Pt[formula omitted]. Similar reactions with Pd(II)-CNR derivatives fail to give any aminooxycarbene compound. The proposed reaction mechanisms for the cyclization reactions of coordinated RNC ligands by 2809 the heterocycles [formula omitted] (Y = NH, S, O) as well as the IR and 1H and 31P NMR spectra of the cyclic carbene products are discussed. © 1988, American Chemical Society. All rights reserved.