Oxalyl halides

Using a Diacyl Dihalide (Oxalyl Halide) or Related Synthon... 

Acyl halides free from traces of phosphorus or sulfur compounds may be made from carboxylic acids and silicon tetrachloride or oxalyl halides (method 339). 

An efficient method for the formal abstraction of oxide from acyl ligands was developed in our laboratory 44). Oxalyl halides react directly with the pentacarbonylmetal acyl complexes of chromium, molybdenum, and tungsten to form the fra ,s-alkylidyne(halo)tetracarbonyl complexes [Eq. (5)]. Other suitable Lewis acids are COCI2, CI3COCI, CI3COCOCI, and... 

The rotational barrier of glyoxal and oxalyl halides has been investigated by Margalef-Roig et al. [12] who have shown that a change of substituent yields a bifurcation. 

Recently Hagen and Hedberg studied several oxalyl halides by electron diffraction. Their data demonstrated the presence of trans-gauche conformers rather than trans-cis conformers. Similar questions regarding orientation about the C-C single bond in the conjugated molecules, biphenyl and the haloderivatives have been extensively studied by Bastiansen and co-workers. ... 

The conversion of aryl allylic alcohols into halogenated vinyl ketones has been achieved (Scheme 7.114) [179]. The process occurred under very mild conditions using oxalyl halides and was generally regioselective for the formation of the a-substitution product. A number of electron-donating and electron-withdrawing groups were well tolerated by the chemistry, provided they were attached to the arene in specific locations. Best results... 

A good starting point for this chemistry would be a allylic alcohol. Conversion of this allylic alcohol into a chlorinated or brominated vinyl ketone can be accomphshed using oxalyl halides [179]. A gold-catalyzed process that affords the iodinated vinyl ketones was successful at room temperature [183]... 

A novel synthesis of metal-carbyne complexes that involves the treatment of metal-acyl derivatives with (COX>2 in dichloromethane has teen desCTited.161 Deoxygenation of [Me4N][M(COR)(CO)5] (M = Cr, Mo, W) with oxalyl halides results in generation of p((CO)4M(CR)] (R = Me, Ph) in good yield,l6i Scheme 8.21 ... 

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