Transition-metal-promoted cyclization reactions of isocyanide ligands. Synthesis of cyclic diaminocarbenes from isocyanide complexes of palladium(II) and platinum(II) and x-ray structure of cis-Br2Pt[CN(C6H4-p-Me)CH2CH2N(H)](PPh3)

Abstract

Electrophilic isocyanide CNR ligands in cationic Pt(II) complexes of the type trans-[(PR’3)2Pt(CNR)Cl]BF4 (I) (PR’3 = PPh3, PMe2Ph; R = p-MeOC6H4, p-MeCaH4, p-NO2C6H4, Me, C6Hll) are converted to the corresponding 5-membered cyclic aminooxycarbene derivatives trans-((PR’3)2Pt[CN(R)CH2CH2O]X)(BF4) (II) (X = Cl, Br) by reaction in THF with 2-bromoethanol in the presence of n-BuLi.