Ketene und aliphatische Diazoverbindungen

A Convenient Ketene Generator

A simple apparatus for the preparation of ketene (CH,--C =O) from acetone vapor is described by Ott, Schr6ter, and Packendofff (1). A more rigid and convenient apparatus has been designed and used by the writer (Fig. 1). Pyrex glass used in both the filamentsupport and bulb reduces the possibility of cracking or breaking. The removable filament-support makes it possible to replace the filament ...

Action of Ketene on Gonadotropic Hormones*

Ketene has been found to be a highly specific,acetylating agent for aqueous solution of proteins. It reacts only with amino, thiol, and phenolic hydroxy groups (1). Several investigators (24) have shown that the primary amino groups react most rapidly, while the hydroxy groups of tyrosine are acetylated at a much slower rate. The hydroxy groups in carbohydrate radicals of the protein molecule d...

Ketene-acetylene [2 + 2] cycloadditions: cyclobutenone and/or oxete formation?

The [2 + 2] cycloaddition of monosubstituted acetylenes to ketene has been studied by ab initio(G2(MP2,SVP) and DFT (B3LYP/6-31Gd)) methods. The activation barrier decreases with increasing electron-donating ability of the acetylene substituent, and it can be roughly correlated with the energy of the acetylene HOMO. The addition to the C[double bond, length as m-dash]C bond of ketene (giving cy...

Catalytic, asymmetric reactions of ketenes and ketene enolates.

Iron-catalyzed alkylation of α-oxo ketene dithioacetals.

Iron-catalyzed alkylation of internal olefins, that is, α-oxo ketene dithioacetals, was successfully realized by using styrenes as the alkylating reagents. Highly functionalized tetrasubstituted olefins were prepared in moderate to high yields.