39195-77-2Relevant academic research and scientific papers
Mechanism of the Photochemical Wolff Rearrangement. The Role of Conformation in the Photolysis of α-Diazo Carbonyl Compounds.
Tomioka, Hideo,Okuno, Hiroshi,Izawa, Yasuji
, p. 5278 - 5283 (1980)
Investigation of photochemical processes of several α-diazo carbonyl compounds reveals that the Wolff rearrangement to form ketene takes place directly from the singlet excited state of the s-Z conformer whereas the excited state of the s-E conformer dissociates nitrogen to generate singlet carbonyl carbene, which either undergoes characteristic carbenic reactions, e.g., insertion and 1,2-hydrogen shift, or gives rise to ketene.The migratory aptitude as well as the relative efficiency of other competing reactions from singlet carbene is shown to be an important factor in dete rmining which reaction pathway is favored.Substantial amounts of singlet carbene can be formed even under sensitized conditions, presumably via intersystem crossing from initially formed triplet carbene.
Oxidation of Thioketenes by Singlet Oxygen
Rao, V. Jayathirtha,Ramamurthy, V.,Schaumann, E.,Nimmesgern, H.
, p. 615 - 621 (2007/10/02)
Oxidation of di-tert-butylthioketene (1) and 1,1,3,3-tetramethyl-2-(thiocarbonyl)cyclohexane (2) by singlet oxygen has been investigated and has been found to exhibit a unique behavior different from that of ketenes and ketenimines.Oxidation of 1 in methylene chloride yielded the corresponding thioketene S-oxide (3), thioketone S-oxide (4), and trans-2,2,7,7-tetramethyl-4-octene-3,6-dione (5), and that in methanol gave 3, 4, methyl 1-tert-butyl-3,3-dimethyl-2-oxobutanesulfinate (6), and 1-methoxy-3,3-dimethylbutanone (7).Similar oxidation of 2 in methylene chloride gave 1,1,3,3-tetramethyl-2-(thiocarbonyl)cyclohexane S-oxide (8), 2,2,6,6-tetramethylcyclohexanethione S-oxide (9), and 2,2,6,6-tetramethylcyclohexanone (10), and in methanol methyl 3,3,7,7-tetramethyl-2-oxocycloheptanesulfinate (11) and 10 were formed.Formation of the above products has been rationalized to arise through the involvement of zwitterionic intermediates (12) resulting from the attack of singlet oxygen on the sulfur lone pair of the thioketene functionality.The difference in behavior between 1 and 2 is suggested to be due to the difference in the nature of cleavage of the suspected intermediate α-peroxythiolactone.Reasons for the variation in the product distribution with respect to temperature and solvent are yet to be understood.
