THERMAL-REACTIONS OF ORGANYL CHALCOGENIDES WITH ALPHA,BETA-UNSATURATED ALDEHYDES

Thermal gas-phase reactions of acrolein, cinnamaldehyde, and benzaldeh yde with diorganyl chalcogenides and diorganyl dichalcogenides were st udied. Acrolein does not react with chalcogenides at 300--600 degrees C but completely decomposes under reaction conditions. At 600-650 degr ees C, cinnamaldehyde reacts only with diorganyl selenides and diselen ides to give benzoselenophene. Its highest yield (53%) is achieved in the reaction with dimethyl diselenide at 630 degrees C and at an equim olar ratio of the reactants. The gas-phase reactions of benzaldehyde a t 400-500 degrees C afford chalcogen-containing derivatives of several types, among which thioanisole and its selenium or tellurium analogs predominate. The mechanisms of the above reactions were discussed in t erms of homolytic substitution of the formyl group at unsaturated carb on atoms by chalcogenyl radicals.