1-hydroxy-pyrrolidine-2,5-dione; tris(4-methoxyphenyl)-phosphine; nBu4NPF6; Ru[P(p-C6H4OCH3)3]2CpCl; sodium hydrogencarbonate in N,N-dimethyl-formamide T=85°C; 23 h;

n-butyllithium; boron trifluoride diethyl etherate in tetrahydrofuran; hexane T=-78°C;