1: 51 percent / diethyl ether / 5 h / 0 °C View Scheme

in tetrahydrofuran addn. of LiC5Me5 in THF to Fe(acac)2 in THF, mixt. was stirred for 0.5 h, NaCpCHO in THF was added, mixt. was stirred overnight; filtn., solvent was removed, 2:1 mixt. of (C5Me5)2Fe and (C5Me5)Fe(C5H4CHO) monitored by NMR;

1: tetrahydrofuran / -5 °C 2: Me2NH / diethyl ether / -40 °C View Scheme