Die Thermolyse oxidierter 1,3‐Dithiolane: Ein neuer Syntheseweg für Thiocarbonyl‐Verbindungen und Sulfine

Thermolysis of Oxidized 1.3‐Dithiolanes: A New Route for the Synthesis of Thiocarbonyl Compounds and Sulfines CF 3 ,‐substituted 1,3‐dithiolanes 3a–c could be synthesized and subsequently oxidized to the 1,3‐dithiolane 1‐oxides 4b,c , 1,1‐dioxides 5a‐c and 1,1,3,3‐tetroxide 6b . The thioketones CF 3 (R)C=S (R = C 6 H 5 , 9a ; CH 3 , 9b ) and the trifluorothioacetaldehyde ( 9c ) could be obtained in good yields by flash vacuum pyrolysis of 5a–c . By further oxidation of 5a–c the 1,3‐dithiolane 1,1,3‐trioxides were formed, and by their pyrolysis the sulfines CF 3 (R)C = SO (R = C 6 H 5 , 10a ; CH 3 , 10b ) were prepared. A unique rearrangement of 7b led to the 1,4‐dithiane 1,1,4‐trioxide 8b . Various Diels‐Alder adducts were synthesized for chemical proof of the existence of 9a–c and 10a, b , and stereochemical considerations are presented.