REACTIVE ARSENIC HETEROCYCLIC-COMPOUNDS .4. TRANSITION-METAL COMPLEXES OF 2,3,4,5-TETRAMETHYLARSOLENE

Tetramethylarsoles R-As-C(Me)=C(Me)-C(Me)=CMe (R = Ph, Me, (t)Bu) have been obtained from Cp2Zr(C4Me4) and RAsCl2. From these a number of complexes of the type M(CO)5 (arsole) (M = Cr, W), cis-W(CO)4 L(arsole) (L = piperidine, iPr3P), [Cp'Mn(CO)(NO)(arsole)]PF6, [CpRu(PR3)2(arsole)]PF6 ((PR3)2 = (PPh3)2, dppm, dpme), and [Cp*RuL2(arsole)]PF6 (L2 = (PMe3)2, norbornadiene) have been prepared through ligand exchange reactions. For R = Me, Ph the complexes readily undergo Diels-Alder-addition with acetylenedicarboxylic acid dimethyl ester. The 7-arsanorbornadienes formed as intermediates are unstable and decompose into arene and arsinidene complex which in one case has been trapped through consecutive insertion reactions.