Cycloadditions copper® cyanide

Conjugate addition, 34-5, 51-2,53, 132, 133 Conjugate hydroxymethylation, 59-60 Copper(n) bromide, 54 Copper([) chloride, 120 Copper(n) chloride, 120 Copper(i) cyanide, 7,52, 53 Copper(i) iodide, 54 Corey s internal quench, 104 Cyanohydrin trimethylsilyl ether, 137 Cycloaddition. 34,112 Cydobutane-l,2-dione, 135 Cyclohept-2-dione, 135 Cyclohex-2-enone, 52,123 Cyclohcxa-1,3-diene, 26 Cyclohexane carboxaldehyde, 22-3,69 73,78... 

The cycloaddition of ethoxycarbonyl azide to racemic O-acetyl cyanohydrin 21 was performed either at 40 °C in acetone or at room temperature and without solvent in the presence of a metal salt (zinc(II) acetate, nickel chloride or copper(I) cyanide) as catalyst54. The required dihydro-triazole 22 (isolated from the 2 1 mixture of regioisomers) was directly converted to the jS-acetoxy amine via migration of the endo-acetoxy group. The Ivans relationship of the hydrogen atoms at C-5 and C-6 was deduced from ll NMR. 

Decomposition of azo compounds to carbenes see also Diazoacetaldehyde, this volume). Huisgen1 was able to stabilize benzoylcarbene (generated from diazoacetophenone) sufficiently to observe 1,3-dipolar cycloadditions by addition of various copper compounds, of which copper (1) cyanide and copper (11) acetyl acetonate appeared to be the most effective. 

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