1: dimethyl 2-(prop-2-ynyl)malonate With sodium hydride in tetrahydrofuran T=20°C; 0.333333 h; 2: methyl 3-methylbut-2-enyl carbonate With tetracarbonylbis(μ-chloro)dirhodium(I) in tetrahydrofuran; N,N-dimethyl-formamide T=-20°C; Further stages.;

1: dimethyl 2-(prop-2-ynyl)malonate With sodium hydride in tetrahydrofuran 0.0833333 h; 2: prenyl bromide in tetrahydrofuran T=23°C; 6 h;

1: dimethyl 2-(prop-2-ynyl)malonate With sodium hydride in tetrahydrofuran T=20°C; 0.333333 h; 2: methyl (2-methyl-3-butene-2-yl)carbonate With tetracarbonylbis(μ-chloro)dirhodium(I) in tetrahydrofuran; N,N-dimethyl-formamide T=-20°C; Further stages. Title compound not separated from byproducts.;

anhydrous propionitrile; tris(propionitrile)tricarbonyltungsten(0) in tetrahydrofuran Ambient temperature; Yield given;

1: potassium carbonate / acetone 2: sodium hydride / diethyl ether View Scheme

sodium hydride in diethyl ether