Cloner - 26-6-2006 at 05:11
While trying to cyclisize (sp?) a diene using maleic anhydride and diels-alder chemistry, I came upon maleic acid chloride as an alternative.
Wikipedia describes this compound under maleic acid, as in it should be formed by thionyl chloride or phosphorus pentachloride action on the maleic
acid. The former reaction in pyridine or DCM gives only carbonaceous detritus with barely a trace of maleic acid or derivatives. Also, it is not for
sale at my usual chemical dealers and I didn't see another reference on the web. Does this compound exist? The best explanation for its rarity would
be that a carboxylic halide would attack the neighbouring group and form the maleic anhydride before a second attack could ever take place. Fumaric
acid chloride exists and reacts diels alder, but it would give a horrible twisted ring in the follow-up so I prefer a cis dicarboxyl.