1: 85 percent / Ba(OH)2 / Heating 2: 57 percent / Zn-Powder, zirconocene dichloride / tetrahydrofuran / 4 h / Ambient temperature 3: H2 / Adams cat. / methanol; acetic acid View Scheme

1: 57 percent / Zn-Powder, zirconocene dichloride / tetrahydrofuran / 4 h / Ambient temperature 2: H2 / Adams cat. / methanol; acetic acid View Scheme

hydrogen; platinum(IV) oxide in methanol; acetic acid Yield given. Yields of byproduct given;

2,2'-azo-bisisobutyronitrile; tri-n-butyl-tin hydride in benzene T=80°C; 17 h; variation of Bu3SnH conc.; rate constant for cyclization; Ea, ΔΔG(excit)(trans/cis); Rate constantMechanismThermodynamic data;

tri-n-butyl-tin hydride in benzene T=80°C; 3 h; Irradiationvariation of Bu3SnH conc.; rate constant for cyclization; Ea, ΔΔG(excit)(trans/cis); Rate constantMechanismThermodynamic data;