1,4-benzoquinone; CO; ethene in methanol-d4 (N2); using Schlenk techniques; charging of NMR tube with a soln. of Pd(OAc)2(dppe) in CD3OD at room temp.; addn. of TsOH and 1,4-benzoquinone; holding for 1 h at room temp., treatment with CO/ethene (1:1) at 40 bar;heating at 85°C for 1 h; not isolated, detected by NMR;