1: dicobalt octacarbonyl; acetylene in dichloromethane T=0 - 20°C; Inert atmosphere; 2: 1,2-propadienylbenzene With 4-methylmorpholine N-oxide in tetrahydrofuran; dichloromethane T=-78 - 20°C; Pauson-Khand reaction; Inert atmosphere; optical yield given as percent de;

in diethyl ether 2 h; Irradiation; Yield given. Yields of byproduct given;